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This  book  should  be  returned  on  or  before  the  date  last  marked  below. 


Edited  by 


With  an  Introduction  by  Dr.  Shapley 

Enlarged  Edition 

with  a  complete,  new  section 
on  atomic  fission 


A  Treasury  of  Science 

COPYRIGHT,   1943,   1946   BY  HARPER  &  BROTHERS 



TABLE       OF       CONTENTS 



ON  SHARING  IN  THE  CONQUESTS  OF  SCIENCE  by  Harlow  Shapley  3 



by  Sir  J.  Arthur  Thomson  and  Patricf^  Geddes 

WE  ARE  ALL  SCIENTISTS  by  T.  H.  Huxley  14 

SCIENTISTS  ARE  LONELY  MEN  by  Oliver  La  Forge  21 

TURTLE  EGGS  FOR  AGASSIZ  by  Dallas  Lore  Sharp  31 


by  Roger  Bacon,  Albert  Einstein,  Sir  Arthur  Eddington, 
Ivan  Pavlov,  and  Raymond  B.  Fosdicf^ 



by  Nicholas  Copernicus 

PROOF  THAT  THE  EARTH  MOVES  by  Galileo  Galilei  58 

THE  ORDERLY  UNIVERSE  by  Forest  Ray  Moulton  .  62 

Is  THERE  LIFE  ON  OTHER  WORLDS?  by  Sir  James  Jeans  83 

THE  MILKY  WAY  AND  BEYOND  by  Sir  Arthur  Eddington  89 


A  YOUNG  MAN  LOOKING  AT  ROCKS  by  Hugh  Miller  97 

GEOLOGICAL  CHANGE  by  Sir  Archibald  Geikf  103 


by  The  Reverend  James  B.  Macelwane,  S.J. 

LAST  DAYS  OF  ST.  PIERRE  by  Fairfax  Downey  118 

MAN,  MAKER  OF  WILDERNESS  by  Paul  B.  Sears  126 

WHAT  MAKES  THE  WEATHER  by  Wolfgang  Langeweische  132 




DISCOVERIES  by  Sir  Isaac  Newton  150 
MATHEMATICS,  THE  MIRROR  OF  CIVILIZATION  by  Lancelot  Hogben          154 

EXPERIMENTS  AND  IDEAS  by  Benjamin  Franklin  168 

1  EXPLORING  THE  ATOM  by  Sir  James  Jeans  175 

TOURING  THE  ATOMIC  WORLD  by  Henry  Schacht  200 

THE  DISCOVERY  OF  RADIUM  by  Eve  Curie  209 

THE  TAMING  OF  ENERGY  by  George  Russell  Harrison  218 

SPACE,  TIME  AND  EINSTEIN  by  Paul  R.  Hey  I  228 


THE  CHEMICAL  REVOLUTION  by  Waldemar  Kaempffert  248 

JETS  POWER  FUTURE  FLYING  by  Watson  Davis  253 

SCIENCE  IN  WAR  AND  AFTER  by  George  Russell  Harrison  257 

Part  Four:  THE  WORLD  OF  LIFE 

THE  NATURE  OF  LIFE  by  W.  J.  V.  Osterhout  273 


by  Sir  /.  Arthur  Thomson  and  Patric\  Geddes 


WHERE  LIFE  BEGINS  by  George  W.  Gray  307 



ON  BEING  THE  RIGHT  SIZE  by  /.  B.  S.  Haldane  321 


by  David  Starr  Jordan  and  Vernon  Lyman  Kellogg 
FLOWERING  EARTH  by  Donald  Culross  Peattie  337 

A  LOBSTER;  OR,  THE  STUDY  OF  ZOOLOGY  by  T.  H.  Huxley  378 


by  David  Starr  Jordan  and  Vernon  Lyman  Kellogg  387 

SECRETS  OF  THE  OCEAN  by  William  Beebe  395 

THE  WARRIOR  ANTS  by  Caryl  P.  Hastens  406 


by  Raymond  L.  Ditmars  and  Arthur  M.  Greenhall 
ANCESTORS  by  Gustav  Eckstein  426 



DARWIN  AND  "THE  ORIGIN  OF  SPECIES"  by  Sir  Arthur  Keith  437 

GREGOR  MENDEL  AND  His  WORK  by  Hugo  lltis  446 

THE  COURTSHIP  OF  ANIMALS  by  Julian  Huxley  453 

MAGIC  ACRES  by  Alfred  Toombs  464 

Part  Five:  THE  WORLD  OF  MAN 



by  Charles  Darwin 

THE  UPSTART  OF  THE  ANIMAL  KINGDOM  by  Earnest  A.  Hooton  481 

MISSING  LINKS  by  John  R.  Baker  491 


LESSONS  IN  LIVING  FROM  THE  STONE  AGE  by  Vilhjalmur  Stefansson  502 

RACIAL  CHARACTERS  OF  THE  BODY  by  Sir  Arthur  Keith  512 


You  AND  HEREDITY  by  Amram  Scheinfeld  521 

BIOGRAPHY  OF  THE  UNBORN  by  Margaret  Shea  Gilbert  540 

How  THE  HUMAN  BODY  Is  STUDIED  by  Sir  Arthur  Keith  551 

VARIATIONS  ON  A  THEME  BY  DARWIN  by  Julian  Huxley  557 



HIPPOCRATES  THE  GREEK — THE  END  OF  MAGIC  by  Logan  Clendening  569 


by  Edward  Jenner 

THE  HISTORY  OF  THE  KINE  Pox  by  Benjamin  Water  house  582 

Louis  PASTEUR  AND  THE  CONQUEST  OF  RABIES  by  Rent  Vallery-Radot  586 

LEPROSY  IN  THE  PHILIPPINES  by  Victor  Heiser  604 

WAR  MEDICINE  AND  WAR  SURGERY  by  George  W.  Gray  623 



THINKING  by  James  Harvey  Robinson  638 

IMAGINATION  CREATRIX  by  John  Livingston  Lowes  650, 

THE  PSYCHOLOGY  OF  SIGMUND  FREUD  by  A.  A.  Brill  655 

BRAIN  STORMS  AND  BRAIN  WAVES  by  George  W.  Gray  673 


WAR  DEPARTMENT  RELEASE  ON  NEW  MEXICO  TEST,  JULY  16,  1945          689 


NUCLEAR  PHYSICS  AND  BIOLOGY  by  E.  O.  Lawrence       -  727 

ALMIGHTY  ATOM  by  John  J.  O'Neill  741 

RELATIONS  by  Jacob  Viner  751 

ATOMIC  WEAPONS  by  J.  R.  Oppenheimer  760 




the  methods  used  in  preparing  it.  We  envisaged  the  audience  as  the 
person  without  specialized  knowledge;  we  accepted  as  our  purpose  to  give 
some  realization  of  how  the  scientist  works,  of  the  body  of  knowledge 
that  has  resulted  and  of  the  excitement  of  the  scientist's  search.  One  of 
us  has  endeavored  to  convey  some  of  that  excitement  in  his  Introduction, 
On  Sharing  in  the  Conquests  of  Science. 

We  realized  that  a  group  of  random  selections,  however  good  in  them- 
selves, would  suggest  little  of  the  unity,  the  architectural  quality  of  science. 
We  spent  some  months  therefore  in  organizing  the  material  before  we 
adopted  a  definite  plan.  The  plan  is  evident  from  the  titles  of  the  major 
Parts:  Science  and  the  Scientist,  The  Physical  World,  The  World  of  Life 
and  The  World  of  Man.  The  subdivisions  carry  through  the  plan  in  what 
seems  a  logical  sequence. 

There  followed  a  period  of  over  a  year  during  which  several  thousand 
books  and  articles  were  examined  in  the  light  of  this  general  scheme. 
In  making  our  selections  we  have  tried  to  emphasize  especially  the  status 
and  the  contributions  of  modern  science,  to  the  end  that  the  reader  can 
bring  himself  abreast  of  current  progress.  But  in  a  few  cases,  we  have 
gone  back  the  better  part  of  a  century  to  find  the  right  discussion.  We 
have  incorporated  a  number  of  biographical  sketches  of  important  scien- 
tists, among  them  Pasteur,  Madame  Curie,  Leeuwenhoek,  in  order  to  give 
a  glimpse  of  the  personalities  of  scientific  explorers.  Also  we  have  reached 
generously  into  the  past  and  selected  classics  of  science,  which  not  only 
add  flavor  but  also  exhibit  the  work  and  workers  who  have  done  so  much 
to  guide  and  inspire  our  civilization. 

It  has  been  found  possible  to  avoid  translations  almost  completely,  since 
the  whole  range  of  modern  science  has  been  explored  assiduously  by 
English-writing  people.  Much  assistance  in  the  preparation  of  a  volume 
of  this  sort  comes  from  the  American  standard  magazines,  and  the  semi- 
popular  scientific  monthlies.  They  have  provided  for  scientific  writers  an 
incentive  to  summarize  their  work  or  the  special  field  concerning  which 


they  write,  in  a  fashion  that  is  comprehensive,  and  comprehensible  to  the 

We  are  also  especially  indebted  to  certain  skillful  scientific  interpreters, 
among  them  the  English  school  of  writers  which  includes  the  Huxleys, 
Sir  J.  A.  Thomson,  Sir  James  Jeans,  and  J.  B.  S.  Haldane.  More  than 
once  we  have  turned  to  their  writings  in  preference  to  the  scattered, 
technical,  fragmentary  originals  from  which  their  synthetic  pictures  are 

Many  important  scientists  are  of  course  not  represented  in  this  collec- 
tion, either  because  their  writings  have  not  been  on  the  appropriate  level, 
or  because  in  our  judgment  the  reader  can  do  better  with  another  writer. 
Limitations  of  space  have  also  shortened  and  compressed  many  of  the 
selections.  And  since  the  volume  is  designed  for  the  general  reader  and 
not  for  the  specialist,  except  when  he  is  also  a  general  reader,  the  addition 
of  references,  technical  footnotes  and  the  similar  apparatus  of  the  serious 
student  are  omitted. 

We  hope  that  the  volume  will  justify  itself  in  interest,  and  in  instruc- 
tional value,  whether  it  is  opened  at  random,  or  is  methodically  read  from 
beginning  to  end.  For  the  reader  who  wishes  to  understand  the  full  mean- 
ing of  any  selection  in  relation  to  its  context,  we  suggest  a  perusal  of  the 
brief  introductory  notes  at  the  beginnings  of  the  main  Parts. 

As  a  general  reference  book  this  volume  should  have  definite  value. 
For  example,  the  attentive  reading  of  Moulton,  Jeans,  and  Eddington  will 
provide  an  authoritative  picture  of  the  fundamentals  as  well  as  the  recent 
advances  of  astronomy;  and  in  short  space  the  reader  can  obtain  from 
Langewiesche  a  fair  understanding  of  modern  weather  prediction.  Several 
contributors  make  atomic  structure  or  the  past  of  man  a  well-rounded 
story.  And  in  a  single  essay  subjects  such  as  the  Metagalaxy,  earthquakes, 
parasitism  or  Freudianism  are  each  clearly  summarized. 

Nevertheless,  the  reader  should  realize  that  this  work  does  not  aim  to 
be  encyclopedic  in  presentation.  It  is  our  hope  that  he  will  go  further  into 
the  vast  stores  of  available  writings  to  get  specialized  knowledge  of  any 
branch  of  science  that  may  interest  him. 

A  contribution  toward  the  integration  of  science  is,  as  we  have  said, 
one  goal  of  this  volume.  We  hope  that  it  may  be  of  particular  value  to 
the  scientific  worker  himself.  No  one  works  effectively  in  more  than 
one  or  two  of  the  special  fields.  The  average  specialist  is  just  as  unin- 
formed about  science  remote  from  his  specialty  as  is  the  general  reader. 
A  familiarity  with  other  disciplines  should  not  only  be  good  entertain- 
ment, but  instructive  as  to  techniques  and  attitudes.  But  of  most  impor- 
tance, the  scientific  specialist,  while  reading  abroad,  is  informing  himself 


on  the  inter-fields  of  science,  or  at  least  on  the  possibility  and  merit  o£ 
inter-field  study.  If  this  volume  can  assist  in  however  small  a  way  in  the 
integration  that  seems  essential  to  man's  intelligent  control  of  his  own 
fabrications,  it  will  have  attained  the  desired  end. 

Preface  to  the  New  Edition 


-**•  and  world-disturbing  consequences  of  the  fission  of  uranium  atoms,  in 
this  second  edition  of  our  Treasury,  can  be  attributed  in  considerable 
part  to  several  episodes,  in  modern  scientific  groping,  that  beautifully 
illustrate  the  interlacing  of  the  various  sciences.  We  now  commonly  under- 
stand that  techniques  devised  by  one  science  may  carry  over  to  another; 
that  results  obtained  in  the  biological  realm  may  provide  a  key  to  mysteries 
that  shroud  the  inanimate. 

But  were  we  prepared  to  find  that  the  study  of  paleozoic  plant  fossil 
would  combine  with  the  theory  of  relativity  to  culminate  in  bombs  that 
frighten  our  civilization?  Half  a  dozen  fields  of  science  have  joined  to 
inaugurate  the  new  age  of  atoms,  rockets,  radar  and  antibiotics.  The 
specialties  contribute  to  astonishing  generalizations  and  to  surprising 
end  results.  Perhaps  our  bringing  of  the  varied  classics  of  science  into 
this  one  large  volume  is  justified  on  the  grounds  that  science,  thought 
and  life  can  be  viewed  as  one  integrated  phenomenon. 

Before  the  somewhat  alarming  release  of  atomic  energy  was  accom- 
plished by  the  nuclear  physicists,  there  were  underlying  basic  contribu- 
tions by  astronomers,  paleontologists,  chemists,  botanists,  geologists  and 
mathematicians.  Some  of  the  critical  steps  can  be  briefly  cited:  the 
discovery  and  interpretation  of  radioactivity  fifty  years  ago;  the  use  of 
the  natural  radioactivity  of  uranium  and  thorium  to  estimate  the  ages 
of  geological  strata;  the  deduction  that  the  life  of  half  a  billion  years 
ago  required  much  the  same  quantity  and  quality  of  sunlight  as  we  now 
receive;  the  conclusion  by  astronomers  that  no  other  source  than  that 
inside  the  atom  could  provide  the  required  amount  and  duration  of 
solar  energy;  the  growing  realization  that  the  energy  in  the  atomic 
nucleus,  as  liberated  in  the  hot  interiors  of  stars  in  accordance  with  the 
principles  of  relativity,  was  the  major  power  source  of  the  universe;  and, 
finally,  the  application  to  uranium  235  of  atom-cracking  and  power-re- 
leasing radiation,  with  epochal  consequences. 

It  has  been  a  glorious  build-up,  involving  the  stars  of  galactic  space  and 
the  atoms  of  the  microcosmos,  and  ending  in  the  urgent  need  that  the 


social  scientists  and  the  practical  citizens  help  to  solve  current  problems, 
both  those  of  saving  ourselves  from  the  danger  of  our  own  ingenuity, 
and  those  of  capitalizing  for  the  good  of  humanity  the  gains  that  are 
now  possible  through  the  advances  of  science. 

The  two  principal  changes  in  the  present  edition  are  the  considerable 
extension  of  the  selection  from  Jeans  "Exploring  the  Atom"  and  the 
supplement  of  several  contributions  relating  to  atomic  energy.  The  reader 
should  not  be  misled  by  the  emphasis  on  uranium  and  plutonium  into 
giving  atomic  energy  exclusive  credit  for  the  atomic  age.  There  are 
many  other  contributors  to  the  scientific  revolution.  Those  popularly 
known  best  are  jet  propulsion,  radar,  penicillin  and  sulfa  drugs,  rocketry, 
blood  derivatives  and  numerous  developments  in  electronic  magic. 

But  back  of  these  modern  evidences  of  human  skill  are  the  conquests 
of  generations  of  scientific  workers  who  could  think  giant  thoughts 
and  fabricate  ingenious  tools  and  theories  without  the  rich  accessories 
now  at  hand.  They  laid  the  foundations  on  which  we  build  foundations 
for  future  builders.  We  hope  that  the  Treasury  of  Science  which  recounts 
many  of  these  adventures  of  the  past  and  present,  will  continue  to 
provide  the  reader  with  building  material  for  his  own  constructions. 




On  Sharing  in  the  Conquests  of  Science 


JL  through  the  damp  woods  back  of  Walden  Pond  with  Henry  Thoreau, 
checking  up  on  the  food  preferences  of  the  marsh  hawk,  and  the  spread 
of  sumach  and  goldenrod  in  old  abandoned  clearings.  It  requires  stamina 
to  match  his  stride  as  he  plunges  through  swamps  and  philosophy, 
through  underbrush,  poetry,  and  natural  history;  it  takes  agility  of  body 
and  mind  if  one  does  a  full  share  of  the  day's  measuring  and  speculation. 

But  no  sooner  have  I  left  the  Walden  Woods  than  I  am  scrambling 
up  the  fossil-rich  Scottish  cliffs  with  Hugh  Miller,  preparing  the  ground- 
work of  the  immortal  history  of  The  Old  Red  Sandstone.  With  the 
wonderment  of  pioneers  we  gaze  at  the  petrified  ripple-marks  that 
some  shallow  receding  sea,  in  ancient  times,  has  left  as  its  fluted  me- 
morial— its  monument  built  on  the  sand  and  of  the  sand,  but  nevertheless 
enduring.  We  break  open  a  stony  ball — this  Scottish  stonemason  and 
I — a  nodular  mass  of  blue  limestone,  and  expose  beautiful  traces  o£ 
an  extinct  world  of  animals  and  plants;  we  find  fossilized  tree  ferns, 
giant  growths  from  the  Carboniferous  Period  of  two  hundred  and  fifty 
million  years  ago — and  forthwith  we  lose  ourselves  in  conjecture. 

And  thea  I  am  off  on  another  high  adventure,  higher  than  the  moon 
this  time;  I  am  entering  the  study  of  the  Frauenburg  Cathedral  to 
help  Nicholas  Copernicus  do  calculations  on  the  hypothetical  motions 
of  the  planets.  He  is,  of  course,  deeply  bemused  with  that  rather  queer 
notion  that  it  might  be  the  Sun  that  stands  still — not  the  Earth.  Perhaps 
he  can  demonstrate  that  the  planets  go  around  the  Sun,  each  in  its  own 
course.  Fascinated,  I  peer  over  his  shoulder  at  the  archaic  geometry, 
watch  his  laborious  penning  of  the  great  book,  and  listen  to  his 
troubled  murmuring  about  the  inaccuracies  of  the  measured  coordinates 
of  Saturn.  "There  are,  you  know,  two  other  big  ones  further  out,"  I  put 
in;  "and  a  system  of  m#ny  moons  around  Jupiter,  which  makes  it  all 
very  clear  and  obvious."  It  must  startle  him  no  end  to  have  me  interrupt 



in  such  a  confident  way.  But  he  does  nothing  about  it.  More  planets?  An 
incredible  idea!  Difficulties  enough  in  trying  to  explain  the  visible, 
without  complicating  the  complexities  further  by  introducing  invisible 
planets.  My  assistance  ignored,  I  experience,  nevertheless,  a  carefree 
exhilaration;  for  I  have,  as  it  were,  matched  my  wits  with  the  wisdom  of 
the  greatest  of  revolutionaries,  and  come  off  not  too  badly! 

Now  that  I  am  fully  launched  in  this  career  of  working  with  the 
great  explorers,  and  of  cooperating  in  their  attacks  on  the  mysteries  of 
the  universe,  I  undertake  further  heroic  assignments.  I  labor  in  the 
laboratories  of  the  world;  I  maintain  fatiguing  vigils  in  the  mountains 
and  on  the  sea,  try  dangerous  experiments,  and  make  strenuous  expedi- 
tions to  Arctic  shores  and  to  torrid  jungles — all  without  moving  from 
the  deep  fireside  chair. 

Benjamin  Franklin  has  a  tempting  idea,  and  I  am  right  there  to  lend 
him  a  hand.  We  are  having  a  lot  of  trouble  in  keeping  that  cantankerous 
kite  in  the  thunder-cloud,  from  which  the  electric  fluid  should  flow  to 
charge  and  animate  the  house  key.  "Before  long,  Sir,  we  shall  run 
printing  presses  with  this  fluid,  and  light  our  houses,  and  talk  around 
the  world"— but  he  does  not  put  it  in  the  Autobiography.  I  am  clearly 
a  century  ahead  of  my  time! 

Youthful  Charles  Darwin  is  in  the  Galapagos.  The  good  brig  Beagle 
stands  offshore.  He  has  with  him  the  collecting  kit,  the  notebooks,  and  his 
curiosity.  He  is  making  records  of  the  slight  variations  among  closely 
similar  species  of  plants  and  animals.  He  is  pondering  the  origin  of  these 
differences,  and  the  origin  of  species,  and  the  whole  confounding  business 
of  the  origin  of  plants  and  animals.  I  sit  facing  him,  on  the  rocks  beside 
the  tide  pool,  admiring  the  penetration  and  grasp  of  this  young  dreamer. 
The  goal  of  his  prolonged  researches  is  a  revolution  in  man's  conception 
of  life;  he  is  assembling  the  facts  and  thoughts,  and  in  this  work  I  am  a 
participant!  Nothing  could  be  more  exciting.  Also  I  have  an  advantage. 
I  know  about  Mendel  and  Mendelian  laws,  and  genes  and  chromosomes. 
I  know  that  X-rays  (unknown  to  Darwin),  and  other  agents,  can 
produce  mutations  and  suddenly  create  living  forms  that  Nature  has 
not  attained.  This  posterior  knowledge  of  mine  enhances  the  pleasure  of 
my  collaboration  with  the  great  naturalist;  and  I  need  have  no  fear  that 
my  information,  or  my  ethereal  presence,  might  bother  him. 

There  is  so  much  scientific  work  of  this  sort  for  me  to  do  before  some 
tormenting  duty  draws  me  out  of  my  strategic  chair.  The  possibilities 
are  nearly  endless.  Like  a  benign  gremlin,  I  sit  on  the  brim  of  a  test 
tube  in  Marie  Curie's  laboratory  and  excitedly  speculate  with  her  on 
that  radioactive  ingredient  in  the  pitchblende;  I  help  name  it  radium. 


With  Stefansson  and  the  Eskimos  I  live  for  months  on  a  scanty  menu, 
and  worry  with  him  about  the  evils  of  civilization.  And  when  young 
Evariste  Galois,  during  his  beautiful,  brief,  perturbed  life  in  Paris,  sits 
down  to  devise  sensationally  new  ideas  and  techniques  in  pure  mathe- 
matics, I  am  right  there  with  applause  and  sympathy. 

Whenever  I  pause  to  appreciate  how  simple  it  is  for  me  to  take  an 
active  part  in  unravelling  the  home  life  of  primitive  man,  or  observing 
the  voracity  of  a  vampire  bat;  how  simple  for  me,  in  company  with  the 
highest  authorities,  to  reason  on  the  theory  of  relativity  or  explore  with 
a  cyclotron  the  insides  of  atoms,  it  is  then  that  I  call  for  additional 
blessings  on  those  artisans  who  invented  printing.  They  have  provided 
me  with  guide  lines  to  remote  wonders — highly  conductive  threads  that 
lead  me,  with  a  velocity  faster  than  that  of  light  itself,  into  times  long  past 
and  into  minds  that  biologically  are  long  extinct.  Through  the  simple 
process  of  learning  how  to  interpret  symbols,  such  as  those  that  make 
this  sentence,  I  can  take  part  in  most  of  the  great  triumphs  of  the  human 
intellect.  Blessings  and  praises,  laurel  wreaths  and  myrtle,  are  due  those 
noble  spirits  who  made  writing  and  reading  easily  accessible,  and  thus 
opened  to  us  all  the  romance  of  scientific  discovery. 

Have  you  ever  heard  an  ox  warble?  Probably  not.  Perhaps  it  goes 
through  its  strange  life-cycle  silent  to  our  gross  ears.  But  I  have  seen  ox 
warbles,  and  through  the  medium  of  the  printed  page  I  have  followed 
their  gory  careers.  The  ox  warbles  to  which  I  refer  are,  of  course,  not 
bovine  melodies,  but  certain  flies  that  contribute  to  the  discomfort  of 
cattle,  to  the  impoverishment  of  man's  property,  and  to  the  enrichment 
of  his  knowledge  of  the  insect  world.1 

It  required  a  declaration  of  war  on  this  entomological  enemy,  by 
some  of  the  great  nations  of  the  planet,  in  order  to  discover  him  com- 
pletely and  entrench  mankind  against  his  depredations.  It  took  a  century 
of  detective  work  on  the  part  of  entomologists  to  lay  bare  the  ox  warble's 
secret  life.  Now  that  I  have  the  story  before  me,  I  can  go  along  with  the 
scientists  and  experience  again  their  campaigns,  their  misadventures,  and 
their  compensating  discoveries.  I  can  see  how  to  connect  a  number 
of  separate  phenomena  that  long  were  puzzling — those  gay  pasture  flies 
that  look  like  little  bumblebees;  those  rows  of  tiny  white  eggs  on  the 
hairs  above  the  hoofs  of  cattle;  the  growing  larvae,  guided  mysteriously 
by  ancestral  experience  to  wind  their  way  for  months  through  the  flesh 
of  the  legs  and  bodies  of  their  unknowing  hosts;  the  apparently  inactive 

1The  full  story  of  the  ox  warble  is  buried  in  various  technical  government  reports.  But 
see  a  brief  chapter  on  the  subject  in  Insects — Man's  Chief  Competitors,  by  W.  P.  Flint  and 
C.  L.  Metcalf  (Williams  &  Wilkins,  1932). 


worms  in  the  cattle's  throats;  the  large  midwinter  mounds,  scattered 
subcutaneously  along  the  spines  of  the  herd;  and  eventually  those  ruin- 
ous holes  in  the  leather,  which  have  forced  governments  into  aggressive 
action — into  defense-with-pursuit  tactics  for  the  protection  of  their  eco- 
nomic frontiers.  It  is  all  clear  now.  During  the  millennia  of  recent  geolog- 
ical periods  a  little  fly  has  learned  how  to  fatten  its  offspring  on  a  fresh 
beef  diet,  and  prepare  its  huge  grub  for  that  critical  moment  when  it 
crawls  out,  through  the  hole  it  has  made  in  the  ox  hide,  and  drops  to 
the  earth  for  its  metamorphosis — the  change  from  a  headless,  legless, 
eyeless,  dark  childhood  to  a  maturity  of  wings  and  sunlight. 

The  curiosity  the  scientist  strives  to  satisfy  is  thus  sometimes  im- 
pelled by  economics;  more  often  by  the  pure  desire  to  know.  Our 
black-on-white  guiding  threads,  which  you  may  call  printed  books,  or 
recorded  history,  not  only  transmit  the  stories  of  ancient  and  modern 
inquisitiveness  and  the  inquiries  it  has  inspired,  but  they  also  report,  to 
the  discerning  recipient,  the  inevitability  of  practiced  internationalism. 
They  transmit  the  message  that  all  races  of  mankind  are  curious  about 
the  universe,  and  that,  when  free  and  not  too  depressed  by  hunger,  men 
instinctively  question  and  explore,  analyze  and  catalogue.  They  have  done 
it  in  all  ages,  in  all  civilized  countries.  They  work  singly,  in  groups, 
and  increasingly  in  world-wide  organizations.  Science  recognizes  no 
impossible  national  boundaries,  and  only  temporary  barriers  of  language. 
It  points  the  way  to  international  cooperation. 

To  more  than  the  art  of  printing,  however,  do  we  owe  the  successes 
and  pleasures  of  our  vicarious  adventures  in  science.  We  are  also  greatly 
indebted  to  those  who  can  write  and  will  write  in  terms  of  our 
limited  comprehension.  Not  all  the  scientists  have  the  facility.  Some- 
times the  talk  is  too  tough  for  us,  or  too  curt.  They  have  not  the  time 
to  be  lucid  on  our  level  and  within  our  vocabulary,  or  perhaps  their 
mental  intensity  has  stunted  the  faculty  of  sympathetic  explanation. 
When  such  technical  barriers  shut  us  from  the  scientific  workshop,  it  is 
then  we  like  to  consult  with  a  clear-spoken  and  understanding  inter- 
preter. We  sit  on  the  back  porch  of  the  laboratory,  while  he,  as  middle- 
man, goes  inside  to  the  obscurities  and  mysteries,  to  return  occasionally 
with  comprehensible  reports.  In  listening  to  him  we  hear  not  only  his 
voice,  but  the  overtones  o£  the  master  he  interprets.  I  like  these  men  of 
understanding  who  play  Boswell  to  the  specialist.  They  often  have  a 
gift  greater  than  that  of  the  concentrated  workers  whom  they  soften 
up  for  us.  For  they  have  breadth  and  perspective,  which  help  us  to 
get  at  the  essence  of  a  problem  more  objectively  than  we  could  even  if 
we  were  fully  equipped  with  the  language  and  knowledge  of  the  fact- 


bent  explorer  and  analyst.  The  scientific  interpreters  frequently  enhance 
our  enjoyment  in  that  they  give  us  of  themselves,  as  well  as  of  the  dis- 
coverers whose  exploits  they  recount.  We  are  always  grateful  to  them, 
moreover,  for  having  spared  us  labor  and  possibly  discouragement. 

Perhaps  the  greatest  satisfaction  in  reading  of  scientific  exploits  and 
participating,  with  active  imagination,  in  the  dull  chores,  the  brave  syn- 
theses, the  hard-won  triumphs  of  scientific  work,  lies  in  the  realization 
that  ours  is  not  an  unrepeatable  experience.  Tomorrow  night  we  can 
again  go  out  among  the  distant  stars.  Again  we  can  drop  cautiously 
below  the  ocean  surface  to  observe  the  unbelievable  forms  that  inhabit 
those  salty  regions  of  high  pressure  and  dim  illumination.  Again  we  can 
assemble  the  myriad  molecules  into  new  combinations,  weave  them 
into  magic  carpets  that  take  us  into  strange  lands  of  beneficent  drugs 
and  of  new  fabrics  and  utensils  destined  to  enrich  the  process  of 
everyday  living.  Again  we  can  be  biologist,  geographer,  astronomer, 
engineer,  or  help  the  philosopher  evaluate  the  nature  and  meaning  of 
natural  laws. 

We  can  return  another  day  to  these  shores,  and  once  more  embark 
for  travels  over  ancient  or  modern  seas  in  quest  of  half-known  lands — 
go  forth  as  dauntless  conquistadores,  outfitted  with  the  maps  and  gear 
provided  through  the  work  of  centuries  of  scientific  adventures. 

But  we  have  done  enough  for  this  day.  We  have  much  to  dream  about. 
Our  appetites  may  have  betrayed  our  ability  to  assimilate.  The  fare  has 
been  irresistibly  palatable.  It  is  time  to  disconnect  the  magic  threads; 
time  to  wind  up  the  spiral  galaxies,  roll  up  the  Milky  Way  and  lay  it 
aside  until  tomorrow. 





been  written.  Many  tales  of  wonder  have  been  told  by  the  great  writers 
of  the  world.  Yet  it  is  common  knowledge  that  the  reality  of  modern  science 
is  more  wonderful  than  the  imaginative  world  of  a  Poe,  a  Wells  or  a 
Jules  Verne.  It  is  therefore  unfortunate  that  the  story  has  usually  been  told  in 
long  words,  written  down  in  forbidding  tomes.  Like  Agassiz's  monumental 
work  on  turtles,  Contributions  to  the  Natural  History  of  the  United  States, 
described  by  Dallas  Lore  Sharp  in  the  following  pages,  they  are  "massive, 
heavy,  weathered  as  if  dug  from  the  rocks/'  Yet  there  is  amusement  in 
science,  excitement,  profound  satisfaction.  It  is  fitting  that  our  first  selection 
should  be  an  attempt  to  describe  that  feeling,  The  Wonder  of  the  World 
by  Sir  /.  Arthur  Thomson  and  Patrick  Geddes. 

Nor  is  science  something  esoteric,  something  mysterious  and  incompre- 
hensible to  the  average  person.  We  are  all  scientists,  as  T.  H.  Huxley  shows 
clearly,  whether  we  are  concerned  with  the  properties  of  green  apples  or 
with  finding  the  burglar  who  stole  our  spoons.  And  we  are  led  to  our  con- 
clusions by  "the  same  train  of  reasoning  which  a  man  of  science  pursues 
when  he  is  endeavoring  to  discover  the  origin  and  laws  of  the  most  occult 
phenomena."  One  of  the  great  scientists  of  the  nineteenth  century,  as  well 
as  its  greatest  scientific  writer,  Huxley  is  well  qualified  to  instruct  us. 

The  quality  that  sets  the  scientist  apart  is  perhaps  the  persistence  of  his 
curiosity  about  the  world.  That  is  what  causes  him  to  bury  himself  in  his 
laboratory  or  travel  to  a  remote  corner  of  the  globe.  Like  Oliver  La  Farge, 
in  Scientists  Are  Lonely  Men,  he  may  spend  months  or  even  years  on  some 
quest,  seeming  trivial  yet  destined  perhaps  to  prove  a  clue  to  the  origin  of  a 
race.  Or  like  Mr.  Jenks  of  Middleboro,  in  Turtle  Eggs  for  Agassiz,  he  may 
spend  countless  hours  beside  a  murky  pond,  waiting  for  a  turtle  to  lay  her 



eggs.  In  both  these  tales  there  is  much  of  the  excitement,  the  emotional  and 
intellectual  spirit  of  the  scientific  quest. 

It  is  not  possible  in  brief  space  to  describe  all  the  aspects  of  that  quest. 
But  in  The  Aims  and  Methods  of  Science,  a  group  of  thinkers  illuminate  a 
few  of  its  many  complexities.  A  passage  from  Roger  Bacon  shows  why  he  is 
considered  one  of  the  originators  of  scientific  method.  Albert  Einstein  asks 
and  answers  the  question,  "Why  does  this  magnificent  applied  science, 
which  saves  work  and  makes  life  easier,  bring  us  so  little  happiness?"  Sir 
Arthur  Eddington  shows  that  again  and  again  the  scientist  must  fly  like 
Icarus,  before  he  finally  reaches  the  sun.  The  passion  of  work  and  research  is 
Ivan  Pavlov's  theme.  In  a  final  selection,  especially  pertinent  today  as  men 
fight,  Raymond  B.  Fosdick  explains  how  the  scientist  cannot  be  bound  by  the 
borders  of  sea  or  land,  how  no  war  can  completely  destroy  his  international 

The  Wonder  of  the  World 


From  Life:  Outlines  of  General  Biology 

•4^.  resolute  thinking,  tells  us  that  throughout  nature  there  is  always 
something  of  the  wonderful — thaumaston.  What  precisely  is  this  "won- 
derful"? It  cannot  be  merely  the  startling,  as  when  we  announce  the  fact 
that  if  we  could  place  in  one  long  row  all  the  hair-like  vessels  or  capillaries 
of  the  human  body,  which  connect  the  ends  of  the  arteries  with  the 
beginnings  of  the  veins,  they  would  reach  across  the  Atlantic.  It  would 
be  all  the  same  to  us  if  they  reached  only  half-way  across.  Nor  can  the 
wonderful  be  merely  the  puzzling,  as  when  we  are  baffled  by  the  "sailing" 
of  an  albatross  round  and  round  our  ship  without  any  perceptible  strokes 
of  its  wings.  For  some  of  these  minor  riddles  are  being  read  every  year, 
without  lessening,  however,  the  fundamental  wonderfulness  of  Nature. 
Indeed,  the  much-abused  word  "wonderful"  is  properly  applied  to  any  fact 
the  knowledge  of  which  greatly  increases  our  appreciation  of  the  signifi- 
cance of  the  system  of  which  we  form  a  part.  The  truly  wonderful  maizes 
all  other  things  deeper  and  higher.  Science  is  always  dispelling  mists — 
the  minor  marvels;  but  it  leaves  us  with  intellectual  blue  sky,  sublime 
mountains,  and  deep  sea.  Their  wonder  appears — and  remains. 

There  seems  to  be  a  rational  basis  for  wonder  in  the  abundance  of  power 
in  the  world — the  power  that  keeps  our  spinning  earth  together  as  it  re- 
volves round  the  sun,  that  keeps  our  solar  system  together  as  it  journeys 
through  space  at  the  rate  of  twelve  miles  a  second  towards  a  point  in  the 
sky,  close  to  the  bright  star  Vega,  called  "the  apex  of  the  sun's  way."  At 
the  other  extreme  there  is  the  power  of  a  fierce  little  world  within  the  com- 
plex atom,  whose  imprisoned  energies  are  set  free  to  keep  up  the  radiant 
energies  of  sun  and  star.  And  between  these  extremes  of  the  infinitely 
great  and  the  infinitely  little  are  the  powers  of  life — the  power  of  winding 
-up  the  clock  almost  as  fast  as  it  runs  down,  the  power  of  a  fish  that  has 



better  engines  than  those  of  a  Mauretania,  life's  power  of  multiplying 
itself,  so  that  in  a  few  hours  an  invisible  microbe  may  become  a  fatal  mil- 

Another,  also  old-fashioned,  basis  for  wonder  is  to  be  found  in  the  im- 
mensities. It  takes  light  eight  minutes  to  reach  us  from  the  sun,  though  it 
travels  at  the  maximum  velocity — of  about  186,300  miles  per  second.  So 
we  see  the  nearest  star  by  the  light  that  left  it  four  years  ago,  and  Vega  as 
it  was  twenty-seven  years  ago,  and  most  of  the  stars  that  we  see  without  a 
telescope  as  they  were  when  Galileo  Galilei  studied  them  in  the  early  years 
of  the  seventeenth  century.  In  any  case  it  is  plain  that  we  are  citizens  of 
no  mean  city. 

A  third  basis  for  rational  wonder  is  to  be  found  in  the  intricacy  and 
manifoldness  of  things.  We  get  a  suggestion  of  endless  resources  in  the 
creation  of  individualities.  Over  two  thousand  years  ago  Aristotle  knew 
about  five  hundred  different  kinds  of  animals;  and  now  the  list  of  the 
named  and  known  includes  twenty-five  thousand  different  kinds  of  back- 
boned animals,  and  a  quarter  of  a  million — some  insist  on  a  minimum  of 
half  a  million — backboneless  animals,  each  itself  and  no  other.  For  "all 
flesh  is  not  the  same  flesh,  but  there  is  one  kind  of  flesh  of  men,  another 
flesh  of  beasts,  another  of  fishes,  and  another  of  birds."  The  blood  of  a 
horse  is  different  from  that  of  an  ass,  and  one  can  often  identify  a  bird 
from  a  single  feather  or  a  fish  from  a  few  scales.  One  is  not  perhaps 
greatly  thrilled  by  the  fact  that  the  average  man  has  twenty-five  billions 
of  oxygen-capturing  red  blood  corpuscles,  which  if  spread  out  would  oc- 
cupy a  surface  of  3,300  square  yards;  but  there  is  significance  in  the  cal- 
culation that  he  has  in  the  cerebral  cortex  of  his  brain,  the  home  of  the 
higher  intellectual  activities,  some  nine  thousand  millions  of  nerve  cells, 
that  is  to  say,  more  than  five  times  the  present  population  of  the  globe — 
surely  more  than  the  said  brain  as  yet  makes  use  of. 

So  it  must  be  granted  that  we  are  fearfully  and  wonderfully  made!  Our 
body  is  built  up  of  millions  of  cells,  yet  there  is  a  simplicity  amid  the 
multitudinousness,  for  each  cell  has  the  same  fundamental  structure. 
Within  the  colloid  cell-substance  there  floats  a  kernel  or  nucleus,  which 
contains  forty-seven  (or  in  woman  forty-eight)  chromosomes,  each  with 
a  bead-like  arrangement  of  smaller  microsomes,  and  so  on,  and  so  on. 
Similarly,  while  eighty-nine  different  elements  have  been  discovered  out 
of  the  theoretically  possible  ninety-two,  we  know  that  they  differ  from 
one  another  only  in  the  number  and  distribution  of  the  electrons  and  pro- 
tons that  make  up  their  microcosmic  planetary  system.  What  artistry  to 
weave  the  gorgeously  varied  tapestry  of  the  world  out  of  two  kinds  of 


physical  thread — besides,  of  course,  Mind,  which  eventually  searches  into 
the  secret  of  the  loom. 

A  fourth  basis  for  rational  wonder  is  in  the  orderliness  of  Nature,  and 
that  is  almost  the  same  thing  as  saying  its  intelligibility.  What  implications 
there  are  in  the  fact  that  man  has  been  able  to  make  a  science  of  Nature! 
Given  three  good  observations  of  a  comet,  the  astronomer  can  predict  its 
return  to  a  night.  It  is  not  a  phantasmagoria  that  we  live  in,  it  is  a  rational- 
isable  cosmos.  The  more  science  advances  the  more  the  fortuitous  shrivels, 
and  the  more  the  power  of  prophecy  grows.  Two  astronomers  foretold  the 
discovery  of  Neptune;  the  chemists  have  anticipated  the  discovery  of  new 
elements;  the  biologist  can  not  only  count  but  portray  his  chickens  before 
they  are  hatched.  The  Order  of  Nature  is  the  largest  of  all  certainties;  and 
leading  authorities  in  modern  physics  tell  us  that  we  cannot  think  of  it  as 
emerging  from  the  fortuitous.  It  is  time  that  the  phrase  "a  fortuitous  con- 
course of  atoms"  was  buried.  Even  the  aboriginal  nebula  was  not  that\  No 
doubt  there  have  been  diseases  and  tragedies  among  men,  cataclysms  and 
volcanic  eruptions  upon  the  earth,  and  so  on — no  one  denies  the  shadows; 
but  even  these  disturbances  are  not  disorderly;  the  larger  fact  is  the  ab- 
sence of  all  caprice.  To  refer  to  the  poet's  famous  line,  no  one  any  longer 
supposes  that  gravitation  can  possibly  cease  when  he  goes  by  the  avalanche. 
Nor  will  a  microbe's  insurgence  be  influenced  by  the  social  importance  of 
the  patient. 

Corresponding  to  the  intelligibility  of  Nature  is  the  pervasiveness  of 
beauty — a  fifth  basis  of  rational  wonder,  appealing  to  the  emotional  side 
of  our  personality.  Surely  Lotze  was  right,  that  it  is  of  high  value  to  look 
upon  beauty  not  as  a  stranger  in  the  world,  nor  as  a  casual  aspect  of  cer- 
tain phenomena,  but  as  "the  fortunate  revelation  of  that  principle  which 
permeates  all  reality  with  its  living  activity." 

A  sixth  basis  of  rational  wonder  is  to  be  found  in  the  essential  character- 
istics of  living  creatures.  We  need  only  add  the  caution  that  the  marvel  of 
life  is  not  to  be  taken  at  its  face  value;  as  Coleridge  wisely  said,  the  first 
wonder  is  the  child  of  ignorance;  we  must  attend  diligently  to  all  that 
biochemistry  and  biophysics  can  discount;  we  must  try  to  understand  all 
that  can  be  formulated  in  terms  of  colloids,  and  so  on.  Yet  when  all  that 
is  said,  there  seem  to  be  large  residual  phenomena  whose  emergence  in 
living  creatures  reveal  a  new  depth  in  Nature.  Life  is  an  enduring,  in- 
surgent activity,  growing,  multiplying,  developing,  enregistering,  varying, 
and  above  all  else  evolving. 

For  this  is  the  seventh  wonder — Evolution.  It  is  not  merely  that  all 
things  flow;  it  is  that  life  flows  uphill.  Amid  the  ceaseless  flux  there  is 
not  only  conservation,  there  is  advancement.  The  changes  are  not  those  of 


a  kaleidoscope,  but  of  "an  onward  advancing  melody."  As  the  unthink- 
ably  long  ages  passed  the  earth  became  the  cradle  and  home  of  life;  nobler 
and  finer  kinds  of  living  creatures  appeared;  there  was  a  growing  vic- 
tory of  life  over  things  and  of  "mind"  over  "body";  until  at  last  appeared 
Man,  who  is  Life's  crowning  wonder,  since  he  has  given  to  everything 
else  a  higher  and  deeper  significance.  And  while  we  must  consider  man 
in  the  light  of  evolution,  as  most  intellectual  combatants  admit,  there  is 
the  even  more  difficult  task  of  envisaging  evolution  in  the  light  of  Man. 
Finis  coronat  opus — a  wise  philosophical  axiom;  and  yet  the  scientist  must 
qualify  it  by  asking  who  can  say  Finis  to  Evolution. 


We  Are  All  Scientists 


From  Darwiniana 

seem  to  suppose,  some  kind  of  modern  black  art.  You  might  easily 
gather  this  impression  from  the  manner  in  which  many  persons  speak  of 
scientific  inquiry,  or  talk  about  inductive  and  deductive  philosophy,  or  the 
principles  of  the  "Baconian  philosophy."  I  do  protest  that,  of  the  vast 
number  of  cants  in  this  world,  there  are  none,  to  my  mind,  so  contempti- 
ble as  the  pseudo-scientific  cant  which  is  talked  about  the  "Baconian 

To  hear  people  talk  about  the  great  Chancellor — and  a  very  great  man 
he  certainly  was, — you  would  think  that  it  was  he  who  had  invented 
science,  and  that  there  was  no  such  thing  as  sound  reasoning  before  the 
time  of  Queen  Elizabeth!  Of  course  you  say,  that  cannot  possibly  be  true; 
you  perceive,  OIL  a  moment's  reflection,  that  such  an  idea  is  absurdly 
wrong.  .  .  . 


The  method  of  scientific  investigation  is  nothing  but  the  expression 
of  the  necessary  mode  of  working  of  the  human  mind.  It  is  simply 
the  mode  at  which  all  phenomena  are  reasoned  about,  rendered  precise 
and  exact.  There  is  no  more  difference,  but  there  is  just  the  same  kind  of 
difference,  between  the  mental  operations  of  a  man  of  science  and  those 
of  an  ordinary  person,  as  there  is  between  the  operations  and  methods  of 
a  baker  or  of  a  butcher  weighing  out  his  goods  in  common  scales,  and  the 
operations  of  a  chemist  in  performing  a  difficult  and  complex  analysis  by 
means  of  his  balance  and  finely-graduated  weights.  It  is  not  that  the  action 
of  the  scales  in  the  one  case,  and  the  balance  in  the  other,  differ  in  the 
principles  of  their  construction  or  manner  of  working;  but  the  beam  of 
one  is  set  on  an  infinitely  finer  axis  than  the  other,  and  of  course  turns  by 
the  addition  of  a  much  smaller  weight. 

You  will  understand  this  better,  perhaps,  if  I  give  you  some  familiar 
example.  You  have  all  heard  it  repeated,  I  dare  say,  that  men  of  science 
work  by  means  of  induction  and  deduction,  and  that  by  the  help  of 
these  operations,  they,  in  a  sort  of  sense,  wring  from  Nature  certain 
other  things,  which  are  called  natural  laws,  and  causes,  and  that  out  of 
these,  by  some  cunning  skill  of  their  own,  they  build  up  hypotheses 
and  theories.  And  it  is  imagined  by  many,  that  the  operations  of  the 
common  mind  can  be  by  no  means  compared  with  these  processes,  and 
that  they  have  to  be  acquired  by  a  sort  of  special  apprenticeship  to  the 
craft.  To  hear  all  these  large  words,  you  would  think  that  the  mind  of 
a  man  of  science  must  be  constituted  differently  from  that  of  his  fellow 
men;  but  if  you  will  not  be  frightened  by  terms,  you  will  discover  that 
you  are  quite  wrong,  and  that  all  these  terrible  apparatus  are  being 
used  by  yourselves  every  day  and  every  hour  of  your  lives. 

There  is  a  well-known  incident  in  one  of  Moliere's  plays,  where  the 
author  makes  the  hero  express  unbounded  delight  on  being  told  that  he 
had  been  talking  prose  during  the  whole  of  his  life.  In  the  same  way, 
I  trust,  that  you  will  take  comfort,  and  be  delighted  with  yourselves,  on 
the  discovery  that  you  have  been  acting  on  the  principles  of  inductive 
and  deductive  philosophy  during  the  same  period.  Probably  there  is  not 
one  who  has  not  in  the  course  of  the  day  had  occasion  to  set  in  motion  a 
complex  train  of  reasoning,  of  the  very  same  kind,  though  differing  of 
course  in  degree,  as  that  which  a  scientific  man  goes  through  in  tracing 
the  causes  of  natural  phenomena. 

A  very  trivial  circumstance  will  serve  to  exemplify  this.  Suppose  you  go 
into  a  fruiterer's  shop,  wanting  an  apple, — you  take  up  one,  and,  on  biting 
it,  you  find  it  is  sour;  you  look  at  it,  and  see  that  it  is  hard  and  green.  You 
take  up  another  one,  and  that  too  is  hard,  green,  and  sour.  The  shopman 


offers  you  a  third;  but,  before  biting  it,  you  examine  it,  and  find  that  it 
is  hard  and  green,  and  you  immediately  say  that  you  will  not  have  it, 
as  it  must  be  sour,  like  those  that  you  have  already  tried. 

Nothing  can  be  more  simple  than  that,  you  think;  but  if  you  will  take 
the  trouble  to  analyse  and  trace  out  into  its  logical  elements  what  has 
been  done  by  the  mind,  you  will  be  greatly  surprised.  In  the  first  place, 
you  have  performed  the  operation  of  induction.  You  found  that,  in  two 
experiences,  hardness  and  greenness  in  apples  went  together  with  sour- 
ness. It  was  so  in  the  first  case,  and  it  was  confirmed  by  the  second.  True, 
it  is  a  very  small  basis,  but  still  it  is  enough  to  make  an  induction  from; 
you  generalise  the  facts,  and  you  expect  to  find  sourness  in  apples  where 
you  get  hardness  and  greenness.  You  found  upon  that  a  general  law,  that 
all  hard  and  green  apples  are  sour;  and  that,  so  far  as  it  goes,  is  a 
perfect  induction.  Well,  having  got  your  natural  law  in  this  way,  when 
you  are  offered  another  apple  which  you  find  is  hard  and  green,  you  say, 
"All  hard  and  green  apples  are  sour;  this  apple  is  hard  and  green,  there- 
fore this  apple  is  sour."  That  train  of  reasoning  is  what  logicians  call  a 
syllogism,  and  has  all  its  various  parts  and  terms — its  major  premiss,  its 
minor  premiss,  and  its  conclusion.  And,  by  the  help  of  further  reason- 
ing, which,  if  drawn  out,  would  have  to  be  exhibited  in  two  or  three  other 
syllogisms,  you  arrive  at  your  final  determination,  "I  will  not  have  that 
apple."  So  that,  you  see,  you  have,  in  the  first  place,  established  a  law  by 
induction,  and  upon  that  you  have  founded  a  deduction,  and  reasoned  out 
the  special  conclusion  of  the  particular  case.  Well  now,  suppose,  having 
got  your  law,  that  at  some  time  afterwards,  you  are  discussing  the  qualities 
of  apples  with  a  friend:  you  will  say  to  him,  "It  is  a  very  curious  thing, — 
but  I  find  that  all  hard  and  green  apples  are  sour!"  Your  friend  says  to 
you,  "But  how  do  you  know  that?"  You  at  once  reply,  "Oh,  because  I  have 
tried  them  over  and  over  again,  and  have  always  found  them  to  be  so." 
Well,  if  we  were  talking  science  instead  of  common  sense,  we  should  call 
that  an  experimental  verification.  And,  if  still  opposed,  you  go  further,  and 
say,  "I  have  heard  from  the  people  in  Somersetshire  and  Devonshire, 
where  a  large  number  of  apples  are  grown,  that  they  have  observed  the 
same  thing.  It  is  also  found  to  be  the  case  in  Normandy,  and  in  North 
America.  In  short,  I  find  it  to  be  the  universal  experience  of  mankind 
wherever  attention  has  been  directed  to  the  subject."  Whereupon,  your 
friend,  unless  he  is  a  very  unreasonable  man,  agrees  with  you,  and  is 
convinced  that  you  are  quite  right  in  the  conclusion  you  have  drawn. 
He  believes,  although  perhaps  he  does  not  know  he  believes  it,  that  the 
more  extensive  verifications  are, — that  the  more  frequently  experiments 
have  been  made,  and  results  of  the  same  kind  arrived  at, — that  the  more 


varied  the  conditions  under  which  the  same  results  are  attained,  the  more 
certain  is  the  ultimate  conclusion,  and  he  disputes  the  question  no  further. 
He  sees  that  the  experiment  has  been  tried  under  all  sorts  of  conditions, 
as  to  time,  place,  and  people,  with  the  same  result;  and  he  says  with  you, 
therefore,  that  the  law  you  have  laid  down  must  be  a  good  one,  and  he 
must  believe  it. 

In  science  we  do  the  same  thing; — the  philosopher  exercises  precisely 
the  same  faculties,  though  in  a  much  more  delicate  manner.  In  scientific 
inquiry  it  becomes  a  matter  of  duty  to  expose  a  supposed  law  to  every 
possible  kind  of  verification,  and  to  take  care,  moreover,  that  this  is  done 
intentionally,  and  not  left  to  a  mere  accident,  as  in  the  case  of  the  apples. 
And  in  science,  as  in  common  life,  our  confidence  in  a  law  is  in  exact  pro- 
portion to  the  absence  of  variation  in  the  result  of  our  experimental  veri- 
fications. For  instance,  if  you  let  go  your  grasp  of  an  article  you  may  have 
in  your  hand,  it  will  immediately  fall  to  the  ground.  That  is  a  very  com- 
mon verification  of  one  of  the  best  established  laws  of  nature — that  of 
gravitation.  The  method  by  which  men  of  science  establish  the  existence 
of  that  law  is  exactly  the  same  as  that  by  which  we  have  established  the 
trivial  proposition  about  the  sourness  of  hard  and  green  apples.  But  we 
believe  it  in  such  an  extensive,  thorough,  and  unhesitating  manner  because 
the  universal  experience  of  mankind  verifies  it,  and  we  can  verify  it  our- 
selves at  any  time;  and  that  is  the  strongest  possible  foundation  on  which 
any  natural  law  can  rest. 

So  much,  then,  by  way  of  proof  that  the  method  of  establishing  laws  in 
science  is  exactly  the  same  as  that  pursued  in  common  life.  Let  us  now 
turn  to  another  matter  (though  really  it  is  but  another  phase  of  the  same 
question),  and  that  is,  the  method  by  which,  from  the  relations  of  certain 
phenomena,  we  prove  that  some  stand  in  the  position  of  causes  towards 
the  others. 

I  want  to  put  the  case  clearly  before  you,  and  I  will  therefore  show  you 
what  I  mean  by  another  familiar  example.  I  will  suppose  that  one  of  you, 
on  coming  down  in  the  morning  to  the  parlour  of  your  house,  finds  that 
a  tea-pot  and  some  spoons  which  had  been  left  in  the  room  on  the  previous 
evening  are  gone, — the  window  is  open,  and  you  observe  the  mark  of  a 
dirty  hand  on  the  window-frame,  and  perhaps,  in  addition  to  that,  you 
notice  the  impress  of  a  hob-nailed  shoe  on  the  gravel  outside.  All  these 
phenomena  have  struck  your  attention  instantly,  and  before  two  seconds 
have  passed  you  say,  "Oh,  somebody  has  broken  open  the  window,  entered 
the  room,  and  run  off  with  the  spoons  and  the  tea-pot!"  That  speech  is  out 
of  your  mouth  in  a  moment.  And  you  will  probably  add,  "I  know  there 
has;  I  am  quite  sure  of  it!"  You  mean  to  say  exactly  what  you  know; 


but  in  reality  you  are  giving  expression  to  what  is,  in  all  essential  partic- 
ulars, an  hypothesis.  You  do  not  \nous  it  at  all;  it  is  nothing  but  an 
hypothesis  rapidly  framed  in  your  own  mind.  And  it  is  an  hypothesis 
founded  on  a  long  train  of  inductions  and  deductions. 

What  are  those  inductions  and  deductions,  and  how  have  you  got  at 
this  hypothesis?  You  have  observed,  in  the  first  place,  that  the  window  is 
open;  but  by  a  train  of  reasoning  involving  many  inductions  and  deduc- 
tions, you  have  probably  arrived  long  before  at  the  general  law — and  a 
very  good  one  it  is — that  windows  do  not  open  of  themselves;  and  you 
therefore  conclude  that  something  has  opened  the  window.  A  second 
general  law  that  you  have  arrived  at  in  the  same  way  is,  that  tea-pots  and 
spoons  do  not  go  out  of  a  window  spontaneously,  and  you  are  satisfied 
that,  as  they  are  not  now  where  you  left  them,  they  have  been  removed. 
In  the  third  place,  you  look  at  the  marks  on  the  window-sill,  and  the  shoe- 
marks  outside,  and  you  say  that  in  all  previous  experience  the  former 
kind  of  mark  has  never  been  produced  by  anything  else  but  the  hand  of 
a  human  being;  and  the  same  experience  shows  that  no  other  animal  but 
man  at  present  wears  shoes  with  hob-nails  in  them  such  as  would  produce 
the  marks  in  the  gravel.  I  do  not  know,  even  if  we  could  discover  any  of 
those  "missing  links"  that  are  talked  about,  that  they  would  help  us  to 
any  other  conclusion!  At  any  rate  the  law  which  states  our  present  experi- 
ence is  strong  enough  for  my  present  purpose.  You  next  reach  the  conclu- 
sion, that  as  these  kinds  of  marks  have  not  been  left  by  any  other  animals 
than  men,  or  are  liable  to  be  formed  in  any  other  way  than  by  a  man's 
hand  and  shoe,  the  marks  in  question  have  been  formed  by  a  man  in  that 
way.  You  have,  further,  a  general  law,  founded  on  observation  and 
experience,  and  that,  too,  is,  I  am  sorry  to  say,  a  very  universal  and  unim- 
peachable one, — that  some  men  are  thieves;  and  you  assume  at  once  from 
all  these  premisses — and  that  is  what  constitutes  your  hypothesis — that  the 
man  who  made  the  marks  outside  and  on  the  window-sill,  opened  the 
window,  got  into  the  room,  and  stole  your  tea-pot  and  spoons.  You  have 
now  arrived  at  a  vera  causa; — you  have  assumed  a  cause  which,  it  is  plain, 
is  competent  to  produce  all  the  phenomena  you  have  observed.  You  can 
explain  all  these  phenomena  only  by  the  hypothesis  of  a  thief.  But  that  is 
a  hypothetical  conclusion,  of  the  justice  of  which  you  have  no  absolute 
proof  at  all;  it  is  only  rendered  highly  probable  by  a  series  of  inductive  and 
deductive  reasonings. 

I  suppose  your  first  action,  assuming  that  you  are  a  man  of  ordinary 
common  sense,  and  that  you  have  established  this  hypothesis  to  your  own 
satisfaction,  will  very  likely  be  to  go  for  the  police,  and  set  them  on  the 
track  of  the  burglar,  with  the  view  to  the  recovery  of  your  property.  But 


just  as  you  are  starting  with  this  object,  some  person  comes  in,  and  on 
learning  what  you  are  about,  says,  "My  good  friend,  you  are  going  on  a 
great  deal  too  fast.  How  do  you  know  that  the  man  who  really  made  the 
marks  took  the  spoons?  It  might  have  been  a  monkey  that  took  them,  and 
the  man  may  have  merely  looked  in  afterwards."  You  would  probably 
reply,  "Well,  that  is  all  very  well,  but  you  see  it  is  contrary  to  all  experience 
of  the  way  tea-pots  and  spoons  are  abstracted;  so  that,  at  any  rate,  your 
hypothesis  is  less  probable  than  mine."  While  you  are  talking  the  thing 
over  in  this  way,  another  friend  arrives.  And  he  might  say,  "Oh,  my  dear 
sir,  you  are  certainly  going  on  a  great  deal  too  fast.  You  are  most  presump- 
tuous. You  admit  that  all  these  occurrences  took  place  when  you  were 
fast  asleep,  at  a  time  when  you  could  not  possibly  have  known  anything 
about  what  was  taking  place.  How  do  you  know  that  the  laws  of  Nature 
are  not  suspended  during  the  night?  It  may  be  that  there  has  been  some 
kind  of  supernatural  interference  in  this  case."  In  point  of  fact,  he  declares 
that  your  hypothesis  is  one  of  which  you  cannot  at  all  demonstrate  the 
truth  and  that  you  are  by  no  means  sure  that  the  laws  of  Nature  are  the 
same  when  you  are  asleep  as  when  you  are  awake. 

Well,  now,  you  cannot  at  the  moment  answer  that  kind  of  reasoning. 
You  feel  that  your  worthy  friend  has  you  somewhat  at  a  disadvantage. 
You  will  feel  perfectly  convinced  in  your  own  mind,  however,  that  you  are 
quite  right,  and  you  say  to  him,  "My  good  friend,  I  can  only  be  guided  by 
the  natural  probabilities  of  the  case,  and  if  you  will  be  kind  enough 
to  stand  aside  and  permit  me  to  pass,  I  will  go  and  fetch  the  police." 
Well,  we  will  suppose  that  your  journey  is  successful,  and  that  by  good 
luck  you  meet  with  a  policeman;  that  eventually  the  burglar  is  found  with 
your  property  on  his  person,  and  the  marks  correspond  to  his  hand  and  to 
his  boots.  Probably  any  jury  would  consider  those  facts  a  very  good 
experimental  verification  of  your  hypothesis,  touching  the  cause  of  the 
abnormal  phenomena  observed  in  your  parlour,  and  would  act  accordingly. 

Now,  in  this  suppositious  case,  I  have  taken  phenomena  of  a  very  com- 
mon kind,  in  order  that  you  might  see  what  are  the  different  steps  in  an 
ordinary  process  of  reasoning,  if  you  will  only  take  the  trouble  to  analyse 
it  carefully.  All  the  operations  I  have  described,  you  will  see,  are  involved 
in  the  mind  of  any  man  of  sense  in  leading  him  to  a  conclusion  as  to  the 
course  he  should  take  in  order  to  make  good  a  robbery  and  punish  the 
offender.  I  say  that  you  are  led,  in  that  case,  to  your  conclusion  by  exactly 
the  same  train  of  reasoning  as  that  which  a  man  of  science  pursues  when 
he  is  endeavouring  to  discover  the  origin  and  laws  of  the  most  occult 
phenomena.  The  process  is,  and  always  must  be,  the  same;  and  precisely 
the  same  mode  of  reasoning  was  employed  by  Newton  and  Laplace  in 


their  endeavours  to  discover  and  define  the  causes  of  the  movements  of 
the  heavenly  bodies,  as  you,  with  your  own  common  sense,  would 
employ  to  detect  a  burglar.  The  only  difference  is,  that  the  nature  of  the 
inquiry  being  more  abstruse,  every  step  has  to  be  most  carefully  watched, 
so  that  there  may  not  be  a  single  crack  or  flaw  in  your  hypothesis.  A 
flaw  or  crack  in  many  of  the  hypotheses  of  daily  life  may  be  of  little  or 
no  moment  as  affecting  the  general  correctness  of  the  conclusions  at  which 
we  may  arrive;  but,  in  a  scientific  inquiry,  a  fallacy,  great  or  small,  is 
always  of  importance,  and  is  sure  to  be  in  the  long  run  constantly  produc- 
tive of  mischievous,  if  not  fatal  results. 

Do  not  allow  yourselves  to  be  misled  by  the  common  notion  that  an 
hypothesis  is  untrustworthy  simply  because  it  is  an  hypothesis.  It  is  often 
urged,  in  respect  to  some  scientific  conclusion,  that,  after  all,  it  is  only  an 
hypothesis.  But  what  more  have  we  to  guide  us  in  nine-tenths  of  the 
most  important  affairs  of  daily  life  than  hypotheses,  and  often  very  ill- 
based  ones?  So  that  in  science,  where  the  evidence  of  an  hypothesis  is 
subjected  to  the  most  rigid  examination,  we  may  rightly  pursue  the  same 
course.  You  may  have  hypotheses  and  hypotheses.  A  man  may  say,  if  he 
likes,  that  the  moon  is  made  of  green  cheese:  that  is  an  hypothesis.  But 
another  man,  who  has  devoted  a  great  deal  of  time  and  attention  to  the 
subject,  and  availed  himself  of  the  most  powerful  telescopes  and  the 
results  of  the  observations  of  others,  declares  that  in  his  opinion  it  is 
probably  composed  of  materials  very  similar  to  those  of  which  our  own 
earth  is  made  up:  and  that  is  also  only  an  hypothesis.  But  I  need  not 
tell  you  that  there  is  an  enormous  difference  in  the  value  of  the  two 
hypotheses.  That  one  which  is  based  on  sound  scientific  knowledge  is  sure 
to  have  a  corresponding  value;  and  that  which  is  a  mere  hasty 
random  guess  is  likely  to  have  but  little  value.  Every  great  step  in  our 
progress  in  discovering  causes  has  been  made  in  exactly  the  same  way  as 
that  which  I  have  detailed  to  you.  A  person  observing  the  occurrence  of 
certain  facts  and  phenomena  asks,  naturally  enough,  what  process,  what 
kind  of  operation  known  to  occur  in  Nature  applied  to  the  particular  case, 
will  unravel  and  explain  the  mystery?  Hence  you  have  the  scientific 
hypothesis;  and  its  value  will  be  proportionate  to  the  care  and  completeness 
with  which  its  basis  has  been  tested  and  verified.  It  is  in  these  matters  as  in 
the  commonest  affairs  of  practical  life:  the  guess  of  the  fool  will  be  folly, 
while  the  guess  of  the  wise  man  will  contain  wisdom.  In  all  cases,  you  see 
that  the  value  of  the  result  depends  on  the  patience  and  faithfulness  with 
which  the  investigator  applies  to  his  hypothesis  every  possible  kind  of 
verification.  .  .  . 


Scientists  Are  Lonely  Men 


study  of  the  science  of  ethnology,  I  corresponded  with  men  in  Ireland, 
Sweden,  Germany,  France,  and  Yucatan,  and  had  some  discussion  with 
a  Chinese.  One  by  one  these  interchanges  were  cut  off;  in  some  countries 
the  concept  of  science  is  dead,  and  even  in  the  free  strongholds  of  Britain 
and  the  Americas  pure  science  is  being — must  be — set  aside  in  favor  of 
what  is  immediately  useful  and  urgently  needed.  It  must  hibernate  now; 
for  a  while  all  it  means  is  likely  to  be  forgotten. 

It  has  never  been  well  understood.  Scientists  have  never  been  good  at 
explaining  themselves  and,  frustrated  by  this,  they  tend  to  withdraw  into 
the  esoteric,  refer  to  the  public  as  "laymen,"  and  develop  incomprehensible 
vocabularies  from  which  they  draw  a  naive,  secret-society  feeling  of 

What  is  the  special  nature  of  a  scientist  as  distinguished  from  a  soda- 
jerker?  Not  just  the  externals  such  as  his  trick  vocabulary,  but  the  human 
formation  within  the  man?  Most  of  what  is  written  about  him  is  rot;  but 
there  is  stuff  there  which  a  writer  can  get  his  teeth  into,  and  it  has  its  vivid, 
direct  relation  to  all  that  we  are  fighting  for. 

The  inner  nature  of  science  within  the  scientist  is  both  emotional  and 
intellectual.  The  emotional  element  must  not  be  overlooked,  for  without 
it  there  is  no  sound  research  on  however  odd  and  dull-seeming  a  subject. 
As  is  true  of  all  of  us,  an  emotion  shapes  and  forms  the  scientist's  life; 
at  the  same  time  an  intellectual  discipline  molds  his  thinking,  stamping 
him  with  a  character  as  marked  as  a  seaman's  although  much  less  widely 

To  an  outsider  who  does  not  know  of  this  emotion,  the  scientist  suggests 
an  ant,  putting  forth  great  efforts  to  lug  one  insignificant  and  apparently 
unimportant  grain  of  sand  to  be  added  to  a  pile,  and  much  of  the  time  his 



struggle  seems  as  pointless  as  an  ant's.  I  can  try  to  explain  why  he  does  it 
and  what  the  long-term  purpose  is  behind  it  through  an  example  from  my 
own  work.  Remember  that  in  this  I  am  not  thinking  of  the  rare,  fortunate 
geniuses  like  the  Curies,  Darwin,  or  Newton,  who  by  their  own  talents 
and  the  apex  of  accumulated  thought  at  which  they  stood  were  knowingly 
in  pursuit  of  great,  major  discoveries.  This  is  the  average  scientist,  one 
among  thousands,  obscure,  unimportant,  toilsome. 

I  have  put  in  a  good  many  months  of  hard  work,  which  ought  by  usual 
standards  to  have  been  dull  but  was  not,  on  an  investigation  as  yet  un- 
finished to  prove  that  Kanhobal,  spoken  by  certain  Indians  in  Guatemala, 
is  not  a  dialect  of  Jacalteca,  but  that,  on  the  contrary,  Jacalteca  is  a  dialect 
of  Kanhobal.  Ridiculous,  isn't  it?  Yet  to  me  the  matter  is  not  only  serious 
but  exciting.  Why  ? 

There  is  an  item  of  glory.  There  are  half  a  dozen  or  so  men  now  living 
(some  now,  unfortunately,  our  enemies)  who  will  pay  me  attention  and 
respect  if  I  prove  my  thesis.  A  slightly  larger  number,  less  interested  in  the 
details  of  my  work,  will  give  credit  to  La  Farge  for  having  added  to  the 
linguistic  map  of  Central  America  the  name  of  a  hitherto  unnoted  dialect. 
But  not  until  I  have  told  a  good  deal  more  can  I  explain — as  I  shall  pres- 
ently— why  the  notice  of  so  few  individuals  can  constitute  a  valid  glory. 

There's  the  nature  of  the  initial  work.  I  have  spent  hours,  deadly,  difficult 
hours,  extracting  lists  of  words,  paradigms  of  verbs,  constructions,  idioms, 
and  the  rest  from  native  informants,  often  at  night  in  over-ventilated  huts 
while  my  hands  turned  blue  with  cold.  (Those  mountains  are  far  from 
tropical.)  An  illiterate  Indian  tires  quickly  when  giving  linguistic  informa- 
tion. He  is  not  accustomed  to  thinking  of  words  in  terms  of  other  words; 
his  command  of  Spanish  is  so  poor  that  again  and  again  you  labor  over 
misunderstandings;  he  does  not  think  in  our  categories  of  words.  Take 
any  schoolchild  and  ask  him  how  you  say,  "I  go."  Then  ask  him  in  turn, 
"Thou  goest,  he  goes,  we  go."  Even  the  most  elementary  schooling  has 
taught  him,  if  only  from  the  force  of  staring  resentfully  at  the  printed 
page,  to  think  in  terms  of  the  present  tense  of  a  single  verb — that  is,  to 
conjugate.  He  will  give  you,  in  Spanish  for  instance,  "Me  voy,  te  vas>  se  va> 
nos  vamos"  &\\  in  order.  Try  this  on  an  illiterate  Indian.  He  gives  you  his 
equivalent  of  "I  go,"  follows  it  perhaps  with  "thou  goest,"  but  the  next 
question  reminds  him  of  his  son's  departure  that  morning  for  Ixtatan,  so 
he  answers  "he  sets  out,"  and  from  that  by  another  mental  leap  produces 
"we  are  traveling."  This  presents  the  investigator  with  a  magnificently 
irregular  verb.  He  starts  checking  back,  and  the  Indian's  mind  being  set 
in  the  new  channel,  he  now  gets  "I  travel"  instead  of  "I  go." 

There  follows  an  exhausting  process  of  inserting  an  alien  concept  into 


the  mind  of  a  man  with  whom  you  are  communicating  tenuously  in  a 
language  which  you  speak  only  pretty  well  and  he  quite  badly. 

Then  of  course  you  come  to  a  verb  which  really  is  irregular  and  you 
mistrust  it.  Both  of  you  become  tired,  frustrated,  upset.  At  the  end  of  an 
hour  or  so  the  Indian  is  worn  out,  his  friendship  for  you  has  materially 
decreased,  and  you  yourself  are  glad  to  quit. 

Hours  and  days  of  this,  and  it's  not  enough.  I  have  put  my  finger  upon 
the  village  of  Santa  Eulalia  and  said,  "Here  is  the  true,  the  classic  Kan- 
hobal  from  which  the  other  dialects  diverge."  Then  I  must  sample  the 
others;  there  are  at  least  eight  villages  which  must  yield  me  up  fairly  com- 
plete word-lists  and  two  from  which  my  material  should  be  as  complete 
as  from  Santa  Eulalia.  More  hours  and  more  days,  long  horseback  trips 
across  the  mountains  to  enter  strange,  suspicious  settlements,  sleep  on  the 
dirt  floor  of  the  schoolhouse,  and  persuade  the  astonished  yokelry  that  it 
is  a  good  idea,  a  delightful  idea,  that  you  should  put  "The  Tongue1'  into 
writing.  Bad  food,  a  bout  of  malaria,  and  the  early-morning  horror  of 
seeing  your  beloved  horse's  neck  running  blood  from  vampire  bats  ("Oh, 
but,  yes,  sefior,  everyone  knows  that  here  are  very  troublesome  the  vam- 
pire bats"),  to  get  the  raw  material  for  proving  that  Jacalteca  is  a  dialect 
of  Kanhobal  instead  of  ... 

You  bring  your  hard-won  data  back  to  the  States  and  you  follow  up  with 
a  sort  of  detective-quest  for  obscure  publications  and  old  manuscripts 
which  may  show  a  couple  of  words  of  the  language  as  it  was  spoken  a 
few  centuries  ago,  so  that  you  can  get  a  line  on  its  evolution.  With  great 
labor  you  unearth  and  read  the  very  little  that  has  been  written  bearing 
upon  this  particular  problem. 

By  now  the  sheer  force  of  effort  expended  gives  your  enterprise  value  in 
your  own  eyes.  And  you  still  have  a  year's  work  to  put  all  your  data  in 
shape,  test  your  conclusions,  and  demonstrate  your  proof. 

Yet  the  real  emotional  drive  goes  beyond  all  this.  Suppose  I  complete  my 
work  and  prove,  in  fact,  that  Kanhobal  as  spoken  in  Santa  Eulalia  is  a 
language  in  its  own  right  and  the  classic  tongue  from  which  Jacalteca  has 
diverged  under  alien  influences,  and  that,  further,  I  show  just  where  the 
gradations  of  speech  in  the  intervening  villages  fit  in.  Dear  God,  what  a 
small,  dull  grain  of  sand! 

But  follow  the  matter  a  little  farther.  Jacalteca  being  relatively  well- 
known  (I  can,  offhand,  name  four  men  who  have  given  it  some  study), 
from  it  it  has  been  deduced  that  this  whole  group  of  dialects  is  most  closely 
related  to  the  languages  spoken  south  and  east  of  these  mountains.  If  my 
theory  is  correct,  the  reverse  is  true — the  group  belongs  to  the  Northern 
Division  of  the  Mayan  Family.  This  fact,  taken  along  with  others  regard- 


ing  physical  appearance,  ancient  remains,  and  present  culture,  leads  to  a 
new  conclusion  about  the  direction  from  which  these  tribes  came  into  the 
mountains:  a  fragment  of  the  ancient  history  of  what  was  once  a  great, 
civilized  people  comes  into  view.  So  now  my  tiny  contribution  begins  to 
be  of  help  to  men  working  in  other  branches  of  anthropology  than  my 
own,  particularly  to  the  archaeologists;  it  begins  to  help  toward  an  even- 
tual understanding  of  the  whole  picture  in  this  area:  the  important  ques- 
tion of,  not  what  these  people  are  to-day,  but  how  they  got  that  way  and 
what  we  can  learn  from  that  about  all  human  behavior  including  our 

Even  carrying  the  line  of  research  as  far  as  this  assumes  that  my  results 
have  been  exploited  by  men  of  greater  attainments  than  I.  Sticking  to  the 
linguistic  line,  an  error  has  been  cleared  away,  an  advance  has  been  made 
in  our  understanding  of  the  layout  and  interrelationship  of  the  many  lan- 
guages making  up  the  Mayan  Family.  With  this  we  come  a  step  nearer  to 
working  out  the  processes  by  which  these  languages  became  different  from 
one  another  and  hence  to  determining  the  archaic,  ancestral  roots  of  the 
whole  group. 

So  far  as  we  know  at  present,  there  are  not  less  than  eight  completely 
unrelated  language  families  in  America  north  of  Panama.  This  is  un- 
reasonable: there  are  hardly  that  many  families  among  all  the  peoples  of 
the  Old  World.  Twenty  years  ago  we  recognized  not  eight,  but  forty. 
Some  day  perhaps  we  shall  cut  the  total  to  four.  The  understanding  of  the 
Mayan  process  is  a  step  toward  that  day;  it  is  unlikely  that  Mayan  will 
remain  an  isolated  way  of  speech  unconnected  with  any  other.  We  know 
now  that  certain  tribes  in  Wyoming  speak  languages  akin  to  those  of 
others  in  Panama;  we  have  charted  the  big  masses  and  islands  of  that 
group  of  tongues  and  from  the  chart  begin  to  see  the  outlines  of  great 
movements  and  crashing  historical  events  in  the  dim  past.  If  we  should 
similarly  develop  a  relationship  between  Mayan  and,  let's  say,  the  lan- 
guages of  the  Mississippi  Valley,  again  we  should  offer  something  provoc- 
ative to  the  archaeologist,  the  historian,  the  student  of  mankind.  Some 
day  we  shall  show  an  unquestionable  kinship  between  some  of  these 
families  and  certain  languages  of  the  Old  World  and  with  it  cast  a  new 
light  on  the  dim  subject  of  the  peopling  of  the  Americas,  something  to 
guide  our  minds  back  past  the  Arctic  to  dark  tribes  moving  blindly  from 
the  high  plateaus  of  Asia. 

My  petty  detail  has  its  place  in  a  long  project  carried  out  by  many  men 
which  will  serve  not  only  the  history  of  language  but  the  broad  scope  of 
history  itself.  It  goes  farther  than  that.  The  humble  Pah-Utes  of  Nevada 
speak  a  tongue  related  to  that  which  the  subtle  Montezuma  used,  the  one 


narrow  in  scope,  evolved  only  to  meet  the  needs  of  a  primitive  people,  the 
other  sophisticated,  a  capable  instrument  for  poetry,  for  an  advanced  gov- 
ernmental system,  and  for  philosophical  speculation.  Men's  thoughts  make 
language  and  their  languages  make  thought.  When  the  matter  of  the 
speech  of  mankind  is  fully  known  and  laid  side  by  side  with  all  the  other 
knowledges,  the  philosophers,  the  men  who  stand  at  the  gathering-together 
point  of  science,  will  have  the  means  to  make  man  understand  himself 
at  last. 

Of  course  no  scientist  can  be  continuously  aware  of  such  remote  possible 
consequences  of  his  labors;  in  fact  the  long  goal  is  so  remote  that  if  he 
kept  his  eyes  on  it  he  would  become  hopelessly  discouraged  over  the  half 
inch  of  progress  his  own  life's  work  will  represent.  But  it  was  the  vision 
of  this  which  first  made  him  choose  his  curious  career,  and  it  is  an  emo- 
tional sense  of  the  great  structure  of  scientific  knowledge  to  which  his 
little  grain  will  be  added  which  drives  him  along. 


I  spoke  of  the  item  of  glory,  the  half  dozen  colleagues  who  will  appre- 
ciate one's  work.  To  understand  that  one  must  first  understand  the  isola- 
tion of  research,  a  factor  which  has  profound  effects  upon  the  scientist's 

The  most  obvious  statement  of  this  is  in  the  public  attitude  and  folk- 
literature  about  "professors."  The  titles  and  subjects  of  Ph.D.  theses  have 
long  been  sources  of  exasperated  humor  among  us;  we  are  all  familiar 
with  the  writer's  device  which  ascribes  to  a  professorial  character  an  in- 
tense interest  in  some  such  matter  as  the  development  of  the  molars  in 
pre-Aurignacian  man  or  the  religious  sanctions  of  the  Levirate  in  north- 
eastern Australia,  the  writer's  intention  being  that  the  reader  shall  say  "Oh 
God!",  smile  slightly,  and  pigeonhole  the  character.  But  what  do  you  sup- 
pose is  the  effect  of  the  quite  natural  public  attitude  behind  these  devices 
upon  the  man  who  is  excitedly  interested  in  pre-Aurignacian  molars  and 
who  knows  that  this  is  a  study  of  key  value  in  tracing  the  evolution  of 
Homo  sapiens? 

Occasionally  some  line  of  research  is  taken  up  and  made  clear,  even  fasci- 
nating, to  the  general  public,  as  in  Zinsser's  Rats,  Lice  and  History,  or  de 
Kruif's  rather  Sunday-supplement  writings.  Usually,  as  in  these  cases,  they 
deal  with  medicine  or  some  other  line  of  work  directly  resulting  in  findings 
of  vital  interest  to  the  public.  Then  the  ordinary  man  will  consent  to  under- 
stand, if  not  the  steps  of  the  research  itself,  at  least  its  importance,  will 
grant  the  excitement,  and  honor  the  researcher.  When  we  read  Eve  Curie's 
great  biography  of  her  parents  our  approach  to  it  is  colored  by  our  knowl- 


edge,  forty  years  later,  of  the  importance  of  their  discovery  to  every  one 
of  us.  It  would  have  been  quite  possible  at  the  time  for  a  malicious  or 
merely  ignorant  writer  to  have  presented  that  couple  as  archetypes  of  the 
"professor,"  performing  incomprehensible  acts  of  self-immolation  in 
pursuit  of  an  astronomically  unimportant  what's-it. 

Diving  to  my  own  experience  like  a  Stuka  with  a  broken  wing,  I  con- 
tinue to  take  my  examples  from  my  rather  shallow  linguistic  studies  be- 
cause, in  its  very  nature,  the  kind  of  thing  a  linguist  studies  is  so  beauti- 
fully calculated  to  arouse  the  "Oh  God!"  emotion. 

It  happened  that  at  the  suggestion  of  my  letters  I  embarked  upon  an 
ambitious,  general  comparative  study  of  the  whole  Mayan  Family.  The 
farther  in  I  got  the  farther  there  was  to  go  and  the  more  absorbed  I  be- 
came. Puzzle  piled  upon  puzzle  to  be  worked  out  and  the  solution  used 
for  getting  after  the  next  one,  the  beginning  of  order  in  chaos,  the  glimpse 
of  understanding  at  the  far  end.  Memory,  reasoning  faculties,  realism,  and 
imagination  were  all  on  the  stretch;  I  was  discovering  the  full  reach  of 
whatever  mental  powers  I  had.  When  I  say  that  I  became  absorbed  I 
mean  absorbed;  the  only  way  to  do  such  research  is  to  roll  in  it,  become 
soaked  in  it,  live  it,  breathe  it,  have  your  system  so  thoroughly  permeated 
with  it  that  at  the  half  glimpse  of  a  fugitive  possibility  everything  you 
have  learned  so  far  and  everything  you  have  been  holding  in  suspension 
is  in  order  and  ready  to  prove  or  disprove  that  point.  You  do  not  only 
think  about  your  subject  while  the  documents  are  spread  before  you; 
everyone  knows  that  some  of  our  best  reasoning  is  done  when  the  surface 
of  the  mind  is  occupied  with  something  else  and  the  deep  machinery  of 
the  brain  is  free  to  work  unhampered. 

One  day  I  was  getting  aboard  a  trolley  car  in  New  Orleans  on  my  way 
to  Tulane  University.  As  I  stepped  up  I  saw  that  if  it  were  possible  to 
prove  that  a  prefixed  s-  could  change  into  a  prefixed  y-  a  whole  series  of 
troublesome  phenomena  would  fall  into  order.  The  transition  must  come 
through  u-  and,  thought  I  with  a  sudden  lift  of  excitement,  there  may  be 
a  breathing  associated  with  u-  and  that  may  make  the  whole  thing  pos- 
sible. As  I  paid  the  conductor  I  thought  that  the  evidence  I  needed  might 
exist  in  Totonac  and  Tarascan,  non-Mayan  languages  with  which  I  was 
not  familiar.  The  possibilities  were  so  tremendous  that  my  heart  pounded 
and  I  was  so  preoccupied  that  I  nearly  went  to  sit  in  the  Jim  Crow  sec- 
tion. Speculation  was  useless  until  I  could  reach  the  University  and  dig 
out  the  books,  so  after  a  while  I  calmed  myself  and  settled  to  my  morning 
ration  of  Popeye,  who  was  then  a  new  discovery  too.  As  a  matter  of  fact, 
the  idea  was  no  good,  but  the  incident  is  a  perfect  example  of  the  "profes- 
sor mind." 


Of  course,  i£  as  I  stepped  on  to  the  car  it  had  dawned  upon  me  that  the 
reason  my  girl's  behavior  last  evening  had  seemed  odd  was  that  she  had 
fallen  for  the  Englishman  we  had  met,  the  incident  would  not  have  seemed 
so  funny,  although  the  nature  of  the  absorption,  subconscious  thinking, 
and  realization  would  have  been  the  same  in  both  cases. 

I  lived  for  a  month  with  the  letter  ^.  If  we  have  three  words  in  Quiche, 
one  of  the  major  Mayan  languages,  beginning  with  ^,  in  Kanhobal  we 
are  likely  to  find  that  one  of  these  begins  with  ch.  Moving  farther  west 
and  north,  in  Tzeltal  one  is  likely  to  begin  with  ^,  one  with  ch,  and  the 
one  which  began  with  ch  in  Kanhobal  to  begin  with  ts.  In  Hausteca,  at 
the  extreme  northwest,  they  begin  with  ^,  ts,  and  plain  s  respectively.  Why 
don't  they  all  change  alike?  Which  is  the  original  form?  Which  way  do 
these  changes  run,  or  from  which  point  do  they  run  both  ways?  Until 
those  questions  can  be  answered  we  cannot  even  guess  at  the  form  of  the 
mother  tongue  from  which  these  languages  diverged,  and  at  that  point  all 
investigation  halts.  Are  these  J(s  in  Quiche  pronounced  even  faintly 
unlike?  I  noticed  no  difference  between  the  two  in  Kanhobal,  but  then  I 
wasn't  listening  for  it.  I  wished  someone  properly  equipped  would  go  and 
listen  to  the  Quiche  Indians,  and  wondered  if  I  could  talk  the  University 
into  giving  me  money  enough  to  do  so. 

This  is  enough  to  give  some  idea  of  the  nature  of  my  work,  and  its  use- 
lessness  for  general  conversation.  My  colleagues  at  Tulane  were  archae- 
ologists. Shortly  after  I  got  up  steam  they  warned  me  frankly  that  I  had 
to  stop  trying  to  tell  them  about  the  variability  of  ^,  the  history  of  Puctun 
tyy  or  any  similar  matter.  If  I  produced  any  results  that  they  could  apply,  I 
could  tell  them  about  it;  but  apart  from  that  I  could  keep  my  damned 
sound-shifts  and  intransitive  infixes  to  myself;  I  was  driving  them  nuts. 
My  other  friends  on  the  faculty  were  a  philosopher  and  two  English  pro- 
fessors; I  was  pursuing  two  girls  at  the  time  but  had  not  been  drawn  to 
either  because  of  intellectual  interests  in  common;  my  closest  friends  were 
two  painters  and  a  sculptor.  The  only  person  I  could  talk  to  was  myself. 

The  cumulative  effect  of  this  non-communication  was  terrific.  A  strange, 
mute  work,  a  thing  crying  aloud  for  discussion,  emotional  expression,  the 
check  and  reassurance  of  another's  point  of  view,  turned  in  upon  myself 
to  boil  and  fume,  throwing  upon  me  the  responsibility  of  being  my  own 
sole  check,  my  own  impersonal,  external  critic.  When  finally  I  came  to 
New  York  on  vacation  I  went  to  see  my  Uncle  John.  He  doesn't  know 
Indian  languages  but  he  is  a  student  of  linguistics,  and  I  shall  never  forget 
the  relief,  the  reveling  pleasure,  of  pouring  my  work  out  to  him. 

Thus  at  the  vital  point  of  his  life-work  the  scientist  is  cut  off  from  com- 
munication with  his  fellow-men.  Instead,  he  has  the  society  of  two,  six,  or 


twenty  men  and  women  who  are  working  in  his  specialty,  with  whom  he 
corresponds,  whose  letters  he  receives  like  a  lover,  with  whom  when  he 
meets  them  he  wallows  in  an  orgy  of  talk,  in  the  keen  pleasure  of  conclu- 
sions and  findings  compared,  matched,  checked  against  one  another — the 
pure  joy  of  being  really  understood. 

The  praise  and  understanding  of  those  two  or  six  become  for  him  the 
equivalent  of  public  recognition.  Around  these  few  close  colleagues  is  the 
larger  group  of  workers  in  the  same  general  field.  They  do  not  share  with 
one  in  the  steps  of  one's  research,  but  they  can  read  the  results,  tell  in  a 
general  way  if  they  have  been  soundly  reached,  and  profit  by  them.  To 
them  McGarnigle  "has  shown"  that  there  are  traces  of  an  ancient,  doli- 
chocephalic strain  among  the  skeletal  remains  from  Pusilha,  which  is 
something  they  can  use.  Largely  on  the  strength  of  his  close  colleagues' 
judgment  of  him,  the  word  gets  round  that  McGarnigle  is  a  sound  man. 
You  can  trust  his  work.  He's  the  fellow  you  want  to  have  analyze  the 
material  if  you  turn  up  an  interesting  bunch  of  skulls.  All  told,  including 
men  in  allied  fields  who  use  his  findings,  some  fifty  scientists  praise  him; 
before  them  he  has  achieved  international  reputation.  He  will  receive  hon- 
ors. It  is  even  remotely  possible  that  he  might  get  a  raise  in  salary. 

McGarnigle  disinters  himself  from  a  sort  of  fortress  made  of  boxes  full 
of  skeletons  in  the  cellar  of  Podunk  University's  Hall  of  Science,  and 
emerges  into  the  light  of  day  to  attend  a  Congress.  At  the  Congress  he 
delivers  a  paper  entitled  Additional  Evidence  of  Dolichocephaly  among 
the  Eighth  Cycle  Maya  before  the  Section  on  Physical  Anthropology.  In 
the  audience  are  six  archaeologists  specializing  in  the  Maya  field,  to  whom 
these  findings  have  a  special  importance,  and  twelve  physical  anthropol- 
ogists including  Gruenwald  of  Eastern  California,  who  is  the  only  other 
man  working  on  Maya  remains. 

After  McGarnigle's  paper  comes  Gruenwald's  turn.  Three  other  physi- 
cal anthropologists,  engaged  in  the  study  of  the  Greenland  Eskimo,  the 
Coastal  Chinese,  and  the  Pleistocene  Man  of  Lake  Mojave  respectively, 
come  in.  They  slipped  out  for  a  quick  one  while  McGarnigle  was  speak- 
ing because  his  Maya  work  is  not  particularly  useful  to  them  and  they  can 
read  the  paper  later;  what  is  coming  next,  with  its  important  bearing  on 
method  and  theory,  they  would  hate  to  miss. 

Gruenwald  is  presenting  a  perfectly  horrible  algebraic  formula  and  a 
diagram  beyond  Rube  Goldberg's  wildest  dream,  showing  A  Formula  for 
Approximating  the  Original  Indices  of  Artificially  Deformed  Crania. 
(These  titles  are  not  mere  parodies;  they  are  entirely  possible.)  The  archae- 
ologists depart  hastily  to  hear  a  paper  in  their  own  section  on  Indica- 
tion^ of  an  Early  Quinary  System  at  Uaxactun.  The  formula  is  intensely 


exciting  to  McGarnigle  because  it  was  the  custom  of  the  ancient  Mayas 
to  remodel  the  heads  of  their  children  into  shapes  which  they  (errone- 
ously) deemed  handsomer  than  nature's.  He  and  Gruenwald  have  been 
corresponding  about  this;  at  one  point  Gruenwald  will  speak  of  his  col- 
league's experience  in  testing  the  formula;  he  has  been  looking  forward 
to  this  moment  for  months. 

After  the  day's  sessions  are  over  will  come  something  else  he  has  been 
looking  forward  to.  He  and  Gruenwald,  who  have  not  seen  each  other  in 
two  years,  go  out  and  get  drunk  together.  It  is  not  that  they  never  get 
drunk  at  home,  but  that  now  when  in  their  cups  they  can  be  uninhibited, 
they  can  talk  their  own,  private,  treble-esoteric  shop.  It  is  an  orgy  of 


In  the  course  of  their  drinking  it  is  likely — if  an  archaeologist  or  two 
from  the  area  joins  them  it  is  certain — that  the  talk  will  veer  from  femoral 
pilasters'  and  alveolar  prognathism  to  personal  experiences  in  remote  sec- 
tions of  the  Peten  jungle.  For  in  my  science  and  a  number  of  others  there 
is  yet  another  frustration. 

We  go  into  the  field  and  there  we  have  interesting  experiences.  The 
word  "adventure"  is  taboo  and  "explore"  is  used  very  gingerly.  But  the 
public  mind  has  been  so  poisoned  by  the  outpourings  of  bogus  explorers 
that  it  is  laden  with  claptrap  about  big  expeditions,  dangers,  hardships, 
hostile  tribes,  the  lighting  of  red  flares  around  the  camp  to  keep  the  sav- 
ages at  bay,  and  God  knows  what  rot.  (I  can  speak  freely  about  this  be- 
cause my  own  expeditions  have  been  so  unambitious  and  in  such  easy 
country  that  I  don't  come  into  the  subject.)  As  a  matter  of  fact  it  is  gen- 
erally true  that  for  a  scientist  on  an  expedition  to  have  an  adventure  is 
evidence  of  a  fault  in  his  technique.  He  is  sent  out  to  gather  information, 
and  he  has  no  business  getting  into  "a  brush  with  the  natives." 

The  red-flare,  into-the-unknown,  hardship-and-danger  boys,  who  man- 
age to  find  a  tribe  of  pink-and-green  Indians,  a  lost  city,  or  the  original, 
handpainted  descendants  of  the  royal  Incas  every  time  they  go  out,  usually 
succeed  in  so  riling  the  natives  and  local  whites  upon  whom  scientists 
must  depend  if  they  are  to  live  in  the  country  as  to  make  work  in  the 
zones  they  contaminate  difficult  for  years  afterward.  The  business  of  their 
adventures  and  discoveries  is  sickening.  .  .  . 

These  men  by  training  express  themselves  in  factual,  "extensional" 
terms,  which  don't  make  for  good  adventure  stories.  They  understand- 
ably lean  over  backward  to  avoid  sounding  even  remotely  like  the  frauds, 


the  "explorers."  And  then  what  they  have  seen  and  done  lacks  validity  to 
them  if  it  cannot  be  told  in  relation  to  the  purpose  and  dominant  emotion 
which  sent  them  there.  McGarnigle  went  among  the  independent  Indians 
of  Icaiche  because  he  had  heard  of  a  skull  kept  in  one  of  their  temples 
which,  from  a  crude  description,  seemed  to  have  certain  important  char- 
acteristics. All  his  risks  and  his  maneuverings  v/ith  those  tough,  explosive 
Indians  centered  around  the  problem  of  gaining  access  to  that  skull.  When 
he  tries  to  tell  an  attractive  girl  about  his  experiences  he  not  only  under- 
states, but  can't  keep  from  stressing  the  significance  of  a  skull  with  a 
healed,  clover-leaf  trepan.  The  girl  gladly  leaves  him  for  the  nearest 
broker.  .  .  . 

It  is  too  bad  both  for  the  scientists  and  the  public  that  they  are  so  cut 
off  from  each  other.  The  world  needs  now  not  the  mere  knowledges  of 
science,  but  the  way  of  thought  and  the  discipline.  It  is  the  essence  of 
what  Hitler  has  set  out  to  destroy;  against  it  he  has  waged  total  war  within 
his  own  domain.  It  is  more  than  skepticism,  the  weighing  of  evidence 
more  even  than  the  love  of  truth.  It  is  the  devotion  of  oneself  to  an  end 
which  is  far  more  important  than  the  individual,  the  certainty  that  the 
end  is  absolutely  good,  not  only  for  oneself  but  for  all  mankind,  and  the 
character  to  set  personal  advantage,  comfort,  and  glory  aside  in  the  de- 
voted effort  to  make  even  a  little  progress  toward  it. 

Turtle  Eggs  for  Agassiz 


-"*  few  books  are  written.  With  every  human  being  a  possible  book,  and 
with  many  a  human  being  capable  of  becoming  more  books  than  the 
world  could  contain,  is  it  not  amazing  that  the  books  of  men  are  so  few? 
And  so  stupid! 

I  took  down,  recently,  from  the  shelves  of  a  great  public  library,  the 
four  volumes  of  Agassiz's  Contributions  to  the  Natural  History  of  the 
United  States.  I  doubt  if  anybody  but  the  charwoman,  with  her  duster, 
had  touched  those  volumes  for  twenty-five  years.  They  are  an  excessively 
learned,  a  monumental,  an  epoch-making  work,  the  fruit  of  vast  and 
heroic  labors,  with  colored  plates  on  stone,  showing  the  turtles  of  the 
United  States,  and  their  embryology.  The  work  was  published  more  than 
half  a  century  ago  (by  subscription) ;  but  it  looked  old  beyond  its  years — 
massive,  heavy,  weathered,  as  if  dug  from  the  rocks.  It  was  difficult  to  feel 
that  Agassiz  could  have  written  it — could  have  built  it,  grown  it,  for  the 
laminated  pile  had  required  for  its  growth  the  patience  and  painstaking 
care  of  a  process  of  nature,  as  if  it  were  a  kind  of  printed  coral  reef.  Agas- 
siz do  this?  The  big,  human,  magnetic  man  at  work  upon  these  pages  of 
capital  letters,  Roman  figures,  brackets,  and  parentheses  in  explanation  of 
the  pages  of  diagrams  and  plates!  I  turned  away  with  a  sigh  from  the 
weary  learning,  to  read  the  preface. 

When  a  great  man  writes  a  great  book  he  usually  flings  a  preface  after 
it,  and  thereby  saves  it,  sometimes,  from  oblivion.  Whether  so  or  not,  the 
best  things  in  most  books  are  their  prefaces.  It  was  not,  however,  the  qual- 
ity of  the  preface  to  these  great  volumes  that  interested  me,  but  rather  the 
wicked  waste  of  durable  book  material  that  went  to  its  making.  Reading 
down  through  the  catalogue  of  human  names  and  of  thanks  for  help  re- 
ceived, I  came  to  a  sentence  beginning: — 

"In  New  England  I  have  myself  collected  largely;  but  I  have  also  re- 



ceived  valuable  contributions  from  the  late  Rev.  Zadoc  Thompson  of  Bur- 
lington .  .  .  from  Mr.  D.  Henry  Thoreau  of  Concord  .  .  .  and  from  Mr. 
J.  W.  P.  Jenks  of  Middleboro."  And  then  it  hastens  on  with  the  thanks  in 
order  to  get  to  the  turtles,  as  if  turtles  were  the  one  and  only  thing  of  real 
importance  in  all  the  world. 

Turtles  no  doubt  are  important,  extremely  important,  embryologically, 
as  part  of  our  genealogical  tree;  but  they  are  away  down  among  the  roots 
of  the  tree  as  compared  with  the  late  Rev.  Zadoc  Thompson  of  Burling- 
ton. I  happen  to  know  nothing  about  the  Rev.  Zadoc,  but  to  me  he  looks 
very  interesting.  Indeed  any  reverend  gentleman  of  his  name  and  day 
who  would  catch  turtles  for  Agassiz  must  have  been  interesting.  And  as 
for  Henry  Thoreau,  we  know  he  was  interesting.  The  rarest  wood  turtle 
in  the  United  States  was  not  so  rare  a  specimen  as  this  gentleman  of  Wai- 
den  Woods  and  Concord.  We  are  glad  even  for  this  line  in  the  preface 
about  him;  glad  to  know  that  he  tried,  in  this  untranscendental  way,  to 
serve  his  day  and  generation.  If  Agassiz  had  only  put  a  chapter  in  his 
turtle  book  about  it!  But  this  is  the  material  he  wasted,  this  and  more  of 
the  same  human  sort,  for  the  Mr.  "Jenks  of  Middleboro"  (at  the  end  of  the 
quotation)  was,  years  later,  an  old  college  professor  of  mine,  who  told  me 
some  of  the  particulars  of  his  turtle  contributions,  particulars  which  Agas- 
siz should  have  found  a  place  for  in  his  big  book.  The  preface  says  merely 
that  this  gentleman  sent  turtles  to  Cambridge  by  the  thousands — brief 
and  scanty  recognition.  For  that  is  not  the  only  thing  this  gentleman  did. 
On  one  occasion  he  sent,  not  turtles,  but  turtle  eggs  to  Cambridge — 
brought  them,  I  should  say;  and  all  there  is  to  show  for  it,  so  far  as  I 
could  discover,  is  a  sectional  drawing  of  a  bit  of  the  mesoblastic  layer  of 
one  of  the  eggs! 

Of  course,  Agassiz  wanted  to  make  that  mesoblastic  drawing,  or  some 
other  equally  important  drawing,  and  had  to  have  the  fresh  turtle  egg  to 
draw  it  from.  He  had  to  have  it,  and  he  got  it.  A  great  man,  when  he 
wants  a  certain  turtle  egg,  at  a  certain  time,  always  gets  it,  for  he  gets 
someone  else  to  get  it.  I  am  glad  he  got  it.  But  what  makes  me  sad  and  im- 
patient is  that  he  did  not  think  it  worth  while  to  tell  about  the  getting  of 
it,  and  so  made  merely  a  learned  turtle  book  of  what  might  have  been  an 
exceedingly  interesting  human  book. 

It  would  seem,  naturally,  that  there  could  be  nothing  unusual  or  inter- 
esting about  the  getting  of  turtle  eggs  when  you  want  them.  Nothing  at 
all,  if  you  should  chance  to  want  the  eggs  as  you  chance  to  find  them.  So 
with  anything  else — good  copper  stock,  for  instance,  if  you  should  chance 
to  want  it,  and  should  chance  to  be  along  when  they  chance  to  be  giving 
it  away.  But  if  you  want  copper  stock,  say  of  C  &  H  quality,  when  you 


want  it,  and  are  bound  to  have  it,  then  you  must  command  more  than  a 
college  professor's  salary.  And  likewise,  precisely,  when  it  is  turtle  eggs 
that  you  are  bound  to  have. 

Agassiz  wanted  those  turtle  eggs  when  he  wanted  them — not  a  minute 
over  three  hours  from  the  minute  they  were  laid.  Yet  even  that  does  not 
seem  exacting,  hardly  more  difficult  than  the  getting  of  hen  eggs  only 
three  hours  old.  Just  so,  provided  the  professor  could  have  had  his  private 
turtle  coop  in  Harvard  Yard;  and  provided  he  could  have  made  his  turtles 
lay.  But  turtles  will  not  respond,  like  hens,  to  meat  scraps  and  the  warm 
mash.  The  professor's  problem  was  not  to  get  from  a  mud  turtle's  nest  in 
the  back  yard  to  the  table  in  the  laboratory;  but  to  get  from  the  laboratory 
in  Cambridge  to  some  pond  when  the  turtles  were  laying,  and  back  to 
the  laboratory  within  the  limited  time.  And  this,  in  the  days  of  Darius 
Green,  might  have  called  for  nice  and  discriminating  work — as  it  did. 

Agassiz  had  been  engaged  for  a  long  time  upon  his  Contributions.  He 
had  brought  the  great  work  nearly  to  a  finish.  It  was,  indeed,  finished  but 
for  one  small  yet  very  important  bit  of  observation:  he  had  carried  the 
turtle  egg  through  every  stage  of  its  development  with  the  single  excep- 
tion of  one — the  very  earliest — that  stage  of  first  cleavages,  when  the  cell 
begins  to  segment,  immediately  upon  its  being  laid.  That  beginning  stage 
had  brought  the  Contributions  to  a  halt.  To  get  eggs  that  were  fresh 
enough  to  show  the  incubation  at  this  period  had  been  impossible. 

There  were  several  ways  that  Agassiz  might  have  proceeded:  he  might 
have  got  a  leave  of  absence  for  the  spring  term,  taken  his  laboratory  to 
some  pond  inhabited  by  turtles,  and  there  camped  until  he  should  catch 
the  reptile  digging  out  her  nest.  But  there  were  difficulties  in  all  of  that — 
as  those  who  are  college  professors  and  naturalists  know.  As  this  was 
quite  out  of  the  question,  he  did  the  easiest  thing — asked  Mr.  "Jenks  of 
Middleboro"  to  get  him  the  eggs.  Mr.  Jenks  got  them.  Agassiz  knew  all 
about  his  getting  of  them;  and  I  say  the  strange  and  irritating  thing  is 
that  Agassiz  did  not  think  it  worth  while  to  tell  us  about  it,  a  least  in  the 
preface  to  his  monumental  work. 

It  was  many  years  later  that  Mr.  Jenks,  then  a  gray-haired  college  pro- 
fessor, told  me  how  he  got  those  eggs  to  Agassiz. 

"I  was  principal  of  an  academy,  during  my  younger  years,"  he  began, 
"and  was  busy  one  day  with  my  classes,  when  a  large  man  suddenly  filled 
the  doorway  of  the  room,  smiled  to  the  four  corners  of  the  room,  and 
called  out  with  a  big,  quick  voice  that  he  was  Professor  Agassiz. 

"Of  course  he  was.  I  knew  it,  even  before  he  had  had  time  to  shout  it 
to  me  across  the  room. 

"Would  I  get  him  some  turtle  eggs?  he  called.  Yes,  I  would.  And  would 


I  get  them  to  Cambridge  within  three  hours  from  the  time  they  were  laid? 
Yes,  I  would.  And  I  did.  And  it  was  worth  the  doing.  But  I  did  it  only 

"When  I  promised  Agassiz  those  eggs  I  knew  where  I  was  going  to 
get  them.  I  had  got  turt  le  eggs  there  before — at  a  particular  patch  of  sandy 
shore  along  a  pond,  a  few  miles  distant  from  the  academy. 

"Three  hours  was  the  limit.  From  the  railroad  station  to  Boston  was 
thirty-five  miles;  from  tiie  pond  to  the  station  was  perhaps  three  or  four 
miles;  from  Boston  to  Cambridge  we  called  about  three  miles.  Forty  miles 
in  round  numbers!  We  figured  it  all  out  before  he  returned,  and  got  the 
trip  down  to  two  hours— record  time:  driving  from  the  pond  to  the  sta- 
tion; from  the  station  by  express  train  to  Boston;  from  Boston  by  cab  to 
Cambridge.  This  left  an  easy  hour  for  accidents  and  delays. 

"Cab  and  car  and  carriage  we  reckoned  into  our  time-table;  but  what 
we  didn't  figure  on  was  the  turtle."  And  he  paused  abruptly. 

"Young  man,"  he  went  on,  his  shaggy  brows  and  spectacles  hardly 
hiding  the  twinkle  in  the  eyes  that  were  bent  severely  upon  me,  "young 
man,  when  you  go  after  turtle  eggs,  take  into  account  the  turtle.  No!  no! 
That's  bad  advice.  Youth  never  reckons  on  the  turtle — and  youth  seldom 
ought  to.  Only  old  age  does  that;  and  old  age  would  never  have  got  those 
turtle  eggs  to  Agassiz. 

"It  was  in  the  early  spring  that  Agassiz  came  to  the  academy,  long 
before  there  was  any  likelihood  of  the  turtles  laying.  But  I  was  eager  for 
the  quest,  and  so  fearful  of  failure  that  I  started  out  to  watch  at  the  pond 
fully  two  weeks  ahead  of  the  time  that  the  turtles  might  be  expected  to 
lay.  I  remember  the  date  clearly:  it  was  May  14. 

"A  little  before  dawn — along  near  three  o'clock — I  would  drive  over  to 
the  pond,  hitch  my  horse  near  by,  settle  myself  quietly  among  some  thick 
cedars  close  to  the  sandy  shore,  and  there  I  would  wait,  my  kettle  of  sand 
ready,  my  eye  covering  the  whole  sleeping  pond.  Here  among  the  cedars  I 
would  eat  my  breakfast,  and  then  get  back  in  good  season  to  open  the 
academy  for  the  morning  session. 

"And  so  the  watch  began. 

"I  soon  came  to  know  individually  the  dozen  or  more  turtles  that  kept 
to  my  side  of  the  pond.  Shortly  after  the  cold  mist  would  lift  and  melt 
away  they  would  stick  up  their  heads  through  the  quiet  water;  and  as  the 
sun  slanted  down  over  the  ragged  rim  of  tree  tops  the  slow  things  would 
float  into  the  warm,  lighted  spots,  or  crawl  out  and  doze  comfortably  on 
the  hummocks  and  snags, 

"What  fragrant  mornings  those  were!  How  fresh  and  new  and  un- 
breathed!  The  pond  odors,  the  woods  odors,  the  odors  of  the  ploughed 


fields — of  water  lily,  and  wild  grape,  and  the  dew-laid  soil!  I  can  taste 
them  yet,  and  hear  them  yet — the  still,  large  sounds  of  the  waking  day — 
the  pickerel  breaking  the  quiet  with  his  swirl;  the  kingfisher  dropping 
anchor;  the  stir  of  feet  and  wings  among  the  trees.  And  then  the  thought 
of  the  great  book  being  held  up  for  me!  Those  were  rare  mornings! 

"But  there  began  to  be  a  good  many  of  them,  for  the  turtles  showed  no 
desire  to  lay.  They  sprawled  in  the  sun,  and  never  one  came  out  upon  the 
sand  as  if  she  intended  to  help  on  the  great  professor's  book.  The  em- 
bryology of  her  eggs  was  of  small  concern  to  her;  her  contribution  to  the 
Natural  History  of  the  United  States  could  wait. 

"And  it  did  wait.  I  began  my  watch  on  the  fourteenth  of  May;  June  first 
found  me  still  among  the  cedars,  still  waiting,  as  I  had  waited  every  morn- 
ing, Sundays  and  rainy  days  alike.  June  first  saw  a  perfect  morning,  but 
every  turtle  slid  out  upon  her  log,  as  if  egg  laying  might  be  a  matter  strictly 
of  next  year. 

"I  began  to  grow  uneasy — not  impatient  yet,  for  a  naturalist  learns  his 
lesson  of  patience  early,  and  for  all  his  years;  but  I  began  to  fear  lest,  by 
some  subtile  sense,  my  presence  might  somehow  be  known  to  the  crea- 
tures; that  they  might  have  gone  to  some  other  place  to  lay,  while  I  was 
away  at  the  schoolroom. 

"I  watched  on  to  the  end  of  the  first  week,  on  to  the  end  of  the  second 
week  in  June,  seeing  the  mists  rise  and  vanish  every  morning,  and  along 
with  them  vanish,  more  and  more,  the  poetry  of  my  early  morning  vigil. 
Poetry  and  rheumatism  cannot  long  dwell  together  in  the  same  clump  of 
cedars,  and  I  had  begun  to  feel  the  rheumatism.  A  month  of  morning 
mists  wrapping  me  around  had  at  last  soaked  through  to  my  bones.  But 
Agassiz  was  waiting,  and  the  world  was  waiting,  for  those  turtle  eggs; 
and  I  would  wait.  It  was  all  I  could  do,  for  there  is  no  use  bringing  a 
china  nest  egg  to  a  turtle;  she  is  not  open  to  any  such  delicate  suggestion. 

"Then  came  a  mid-June  Sunday  morning,  with  dawn  breaking  a  little 
after  three:  a  warm,  wide-awake  dawn,  with  the  level  mist  lifted  from  the 
level  surface  of  the  pond  a  full  hour  higher  than  I  had  seen  it  any  morning 

"This  was  the  day:  I  knew  it.  I  have  heard  persons  say  that  they  can 
hear  the  grass  grow;  that  they  know  by  some  extra  sense  when  danger  is 
nigh.  That  we  have  these  extra  senses  I  fully  believe,  and  I  believe  they  can 
be  sharpened  by  cultivation.  For  a  month  I  had  been  watching,  brooding 
over  this  pond,  and  now  I  knew.  I  felt  a  stirring  of  the  pulse  of  things 
that  the  cold-hearted  turtles  could  no  more  escape  than  could  the  clods 
and  I. 

"Leaving  my  horse  unhitched,  as  if  he  too  understood,  I  slipped  eagerly 


into  my  covert  for  a  look  at  the  pond.  As  I  did  so,  a  large  pickerel 
ploughed  a  furrow  out  through  the  spatter-docks,  and  in  his  wake  rose 
the  head  of  an  enormous  turtle.  Swinging  slowly  around,  the  creature 
headed  straight  for  the  shore,  and  without  a  pause  scrambled  out  on  the 

"She  was  about  the  size  of  a  big  scoop  shovel;  but  that  was  not  what 
excited  me,  so  much  as  her  manner,  and  the  gait  at  which  she  moved;  for 
there  was  method  in  it,  and  fixed  purpose.  On  she  came,  shuffling  over  the 
sand  toward  the  higher  open  fields,  with  a  hurried,  determined  seesaw 
that  was  taking  her  somewhere  in  particular,  and  that  was  bound  to  get 
her  there  on  time. 

"I  held  my  breath.  Had  she  been  a  dinosaurian  making  Mesozoic  foot- 
prints, I  could  not  have  been  more  fearful.  For  footprints  in  the  Mesozoic 
mud,  or  in  the  sands  of  time,  were  as  nothing  to  me  when  compared  with 
fresh  turtle  eggs  in  the  sands  of  this  pond. 

"But  over  the  strip  of  sand,  without  a  stop,  she  paddled,  and  up  a 
narrow  cow  path  into  the  high  grass  along  a  fence.  Then  up  the  narrow 
cow  path,  on  all  fours,  just  like  another  turtle,  I  paddled,  and  into  the 
high  wet  grass  along  the  fence. 

"I  kept  well  within  sound  of  her,  for  she  moved  recklessly,  leaving  a 
trail  of  flattened  grass  a  foot  and  a  half  wide.  I  wanted  to  stand  up, — and  I 
don't  believe  I  could  have  turned  her  back  with  a  rail, — but  I  was  afraid 
if  she  saw  me  that  she  might  return  indefinitely  to  the  pond;  so  on  I 
went,  flat  to  the  ground,  squeezing  through  the  lower  rails  of  the  fence, 
as  if  the  field  beyond  were  a  melon  patch.  It  was  nothing  of  the  kind,  only 
a  wild,  uncomfortable  pasture,  full  of  dewberry  vines,  and  very  dis- 
couraging. They  were  excessively  wet  vines  and  briery.  I  pulled  my  coat 
sleeves  as  far  over  my  fists  as  I  could  get  them,  and,  with  the  tin  pail  of 
sand  swinging  from  between  my  teeth  to  avoid  noise,  I  stumped  fiercely, 
but  silently,  on  after  the  turtle. 

"She  was  laying  her  course,  I  thought,  straight  down  the  length  of  this 
dreadful  pasture,  when,  not  far  from  the  fence,  she  suddenly  hove  to, 
warped  herself  short  about,  and  came  back,  barely  clearing  me,  at  a  clip 
that  was  thrilling.  I  warped  about,  too,  and  in  her  wake  bore  down 
across  the  corner  of  the  pasture,  across  the  powdery  public  road,  and  on  to 
a  fence  along  a  field  of  young  corn. 

"I  was  somewhat  wet  by  this  time,  but  not  so  wet  as  I  had  been  before, 
wallowing  through  the  deep  dry  dust  of  the  road.  Hurrying  up  behind  a 
large  tree  by  the  fence,  I  peered  down  the  corn  rows  and  saw  the  turtle 
stop,  and  begin  to  paw  about  in  the  loose  soft  soil.  She  was  going  to  lay! 

"I  held  on  to  the  tree  and  watched,  as  she  tried  this  place,  and  that  place, 


and  the  other  place — the  eternally  feminine!  But  the  place,  evidently,  was 
hard  to  find.  What  could  a  female  turtle  do  with  a  whole  field  of  possible 
nests  to  choose  from?  Then  at  last  she  found  it,  and,  whirling  about,  she 
backed  quickly  at  it,  and,  tail  first,  began  to  bury  herself  before  my  staring 

"Those  were  not  the  supreme  moments  of  my  life;  perhaps  those 
moments  came  later  that  day;  but  those  certainly  were  among  the  slowest, 
most  dreadfully  mixed  of  moments  that  I  ever  experienced.  They  were 
hours  long.  There  she  was,  her  shell  just  showing,  like  some  old  hulk  in 
the  sand  alongshore.  And  how  long  would  she  stay  there?  And  how 
should  I  know  if  she  had  laid  an  egg? 

"I  could  still  wait.  And  so  I  waited,  when,  over  the  freshly  awakened 
fields,  floated  four  mellow  strokes  from  the  distant  town  clock. 

"Four  o'clock!  Why,  there  was  no  train  until  seven  1  No  train  for  three 
hours!  The  eggs  would  spoil!  Then  with  a  rush  it  came  over  me  that  this 
was  Sunday  morning,  and  there  was  no  regular  seven  o'clock  train — none 
till  after  nine. 

"I  think  I  should  have  fainted  had  not  the  turtle  just  then  begun 
crawling  off.  I  was  weak  and  dizzy;  but  there,  there  in  the  sand,  were  the 
eggs!  And  Agassiz!  And  the  great  book!  And  I  cleared  the  fence,  and  the 
forty  miles  that  lay  between  me  and  Cambridge,  at  a  single  jump.  He 
should  have  them,  trains  or  no.  Those  eggs  should  go  to  Agassiz  by  seven 
o'clock,  if  I  had  to  gallop  every  mile  of  the  way.  Forty  miles!  Any  horse 
could  cover  it  in  three  hours,  if  he  had  to;  and,  upsetting  the  astonished 
turtle,  I  scooped  out  her  round  white  eggs. 

"On  a  bed  of  sand  in  the  bottom  of  the  pail  I  laid  them,  with  what 
care  my  trembling  fingers  allowed;  filled  in  between  them  with  more 
sand;  so  with  another  layer  to  the  rim;  and,  covering  all  smoothly  with 
more  sand,  I  ran  back  for  my  horse. 

"That  horse  knew,  as  well  as  I,  that  the  turtle  had  laid,  and  that  he 
was  to  get  those  eggs  to  Agassiz.  He  turned  out  of  that  field  into  the  road 
on  two  wheels,  a  thing  he  had  not  done  for  twenty  years,  doubling  me  up 
before  the  dashboard,  the  pail  of  eggs  miraculously  lodged  between  my 

"I  let  him  out.  If  only  he  could  keep  this  pace  all  the  way  to  Cambridge! 
Or  even  halfway  there;  and  I  should  have  time  to  finish  the  trip  on  foot. 
I  shouted  him  on,  holding  to  the  dasher  with  one  hand,  the  pail  of  eggs 
with  the  other,  not  daring  to  get  off  my  knees,  though  the  bang  on  them, 
as  we  pounded  down  the  wood  road,  was  terrific.  But  nothing  must 
happen  to  the  eggs;  they  must  not  be  jarred,  or  even  turned  over  in  the 
sand  before  they  come  tc?  Agassiz. 


"In  order  to  get  out  on  the  pike  it  was  necessary  to  drive  back  away 
from  Boston  toward  the  town.  We  had  nearly  covered  the  distance,  and 
were  rounding  a  turn  from  the  woods  into  the  open  fields,  when,  ahead 
of  me,  at  the  station  it  seemed,  I  heard  the  quick  sharp  whistle  of  a  loco- 

"What  did  it  mean?  Then  followed  the  puff,  pufff  puff  of  a  starting 
train.  But  what  train?  Which  way  going?  And,  jumping  to  my  feet  for  a 
longer  view,  I  pulled  into  a  side  road  that  paralleled  the  track,  and  headed 
hard  for  the  station. 

"We  reeled  along.  The  station  was  still  out  of  sight,  but  from  behind  the 
bushes  that  shut  it  from  view  rose  the  smoke  of  a  moving  engine.  It  was 
perhaps  a  mile  away,  but  we  were  approaching,  head-on,  and,  topping  a 
little  hill,  I  swept  down  upon  a  freight  train,  the  black  smoke  pouring 
from  the  stack,  as  the  mighty  creature  pulled  itself  together  for  its  swift 
run  down  the  rails. 

"My  horse  was  on  the  gallop,  going  with  the  track,  and  straight  toward 
the  coming  train.  The  sight  of  it  almost  maddened  me — the  bare  thought 
of  it,  on  the  road  to  Boston!  On  I  went;  on  it  came,  a  half— a  quarter  of  a 
mile  between  us,  when  suddenly  my  road  shot  out  along  an  unfenced  field 
with  only  a  level  stretch  of  sod  between  me  and  the  engine. 

"With  a  pull  that  lifted  the  horse  from  his  feet,  I  swung  him  into  the 
field  and  sent  him  straight  as  an  arrow  for  the  track.  That  train  should 
carry  me  and  my  eggs  to  Boston! 

"The  engineer  pulled  the  rope.  He  saw  me  standing  up  in  the  rig,  saw 
my  hat  blow  off,  saw  me  wave  my  arms,  saw  the  tin  pail  swing  in  my 
teeth,  and  he  jerked  out  a  succession  of  sharp  halts!  But  it  was  he  who 
should  halt,  not  I;  and  on  we  went,  the  horse  with  a  flounder  landing  the 
carriage  on  top  of  the  track. 

"The  train  was  already  grinding  to  a  stop;  but  before  it  was  near  a 
stand-still  I  had  backed  off  the  track,  jumped  out,  and,  running  down  the 
rails  with  the  astonished  engineers  gaping  at  me,  had  swung  aboard  the 

"They  offered  no  resistance;  they  hadn't  had  time.  Nor  did  they  have 
the  disposition,  for  I  looked  strange,  not  to  say  dangerous.  Hatless,  dew- 
soaked,  smeared  with  yellow  mud,  and  holding,  as  if  it  were  a  baby  or  a 
bomb,  a  little  tin  pail  of  sand. 

"  'Crazy,'  the  fireman  muttered,  looking  to  the  engineer  for  his  cue. 

"I  had  been  crazy,  perhaps,  but  I  was  not  crazy  now. 

"'Throw  her  wide  open,'  I  commanded.  'Wide  open!  These  are  fresh 
turtle  eggs  for  Professor  Agassiz  of  Cambridge.  He  must  have  them  before 


"Then  they  knew  I  was  crazy,  and,  evidently  thinking  it  best  to  humor 
me,  threw  the  throttle  wide  open,  and  away  we  went. 

"I  kissed  my  hand  to  the  horse,  grazing  unconcernedly  in  the  open  field, 
and  gave  a  smile  to  my  crew.  That  was  all  I  could  give  them,  and  hold 
myself  and  the  eggs  together.  But  the  smile  was  enough.  And  they  smiled 
through  their  smut  at  me,  though  one  of  them  held  fast  to  his  shovel, 
while  the  other  kept  his  hand  upon  a  big  ugly  wrench.  Neither  of  them 
spoke  to  me,  but  above  the  roar  of  the  swaying  engine  I  caught  enough  of 
their  broken  talk  to  understand  that  they  were  driving  under  a  full  head  of 
steam,  with  the  intention  of  handing  me  over  to  the  Boston  police,  as 
perhaps  the  easiest  way  of  disposing  of  me. 

"I  was  only  afraid  that  they  would  try  it  at  the  next  station.  But  that 
station  whizzed  past  without  a  bit  of  slack,  and  the  next,  and  the  next; 
when  it  came  over  me  that  this  was  the  through  freight,  which  should 
have  passed  in  the  night,  and  was  making  up  lost  time. 

"Only  the  fear  of  the  shovel  and  the  wrench  kept  me  from  shaking 
hands  with  both  men  at  this  discovery.  But  I  beamed  at  them;  and  they  at 
me.  I  was  enjoying  it.  The  unwonted  jar  beneath  my  feet  was  wrinkling 
my  diaphragm  with  spasms  of  delight.  And  the  fireman  beamed  at  the 
engineer,  with  a  look  that  said,  'See  the  lunatic  grin;  he  likes  it!' 

"He  did  like  it.  How  the  iron  wheels  sang  to  me  as  they  took  the  rails! 
How  the  rushing  wind  in  my  ears  sang  to  me!  From  my  stand  on  the  fire- 
man's side  of  the  cab  I  could  catch  a  glimpse  of  the  track  just  ahead  of  the 
engine,  where  the  ties  seemed  to  leap  into  the  throat  of  the  mile-devouring 
monster.  The  joy  of  it!  Of  seeing  space  swallowed  by  the  mile! 

"I  shifted  the  eggs  from  hand  to  hand  and  thought  of  my  horse,  of 
Agassiz,  of  the  great  book,  of  my  great  luck, — luck, — luck, — until  the 
multitudinous  tongues  of  the  thundering  train  were  all  chiming  'luck! 
luck!  luck!'  They  knew!  They  understood!  This  beast  of  fire  and  tireless 
wheels  was  doing  its  very  best  to  get  the  eggs  to  Agassiz! 

"We  swung  out  past  the  Blue  Hills,  and  yonder  flashed  the  morning 
sun  from  the  towering  dome  of  the  State  House.  I  might  have  leaped  from 
the  cab  and  run  the  rest  of  the  way  on  foot,  had  I  not  caught  the  eye  of 
the  engineer  watching  me  narrowly.  I  was  not  in  Boston  yet,  nor  in 
Cambridge  either.  I  was  an  escaped  lunatic,  who  had  held  up  a  train,  and 
forced  it  to  carry  me  to  Boston. 

"Perhaps  I  had  overdone  my  lunacy  business.  Suppose  these  two  men 
should  take  it  into  their  heads  to  turn  me  over  to  the  police,  whether  I 
would  or  no?  I  could  never  explain  the  case  in  time  to  get  the  eggs  to 
Agassiz.  I  looked  at  my  watch.  There  were  still  a  few  minutes  left,  in 
which  I  might  explain  to  these  men,  who,  all  at  once,  had  become  my 


captors.  But  it  was  too  late.  Nothing  could  avail  against  my  actions,  my 
appearance,  and  my  little  pail  of  sand. 

"I  had  not  thought  of  my  appearance  before.  Here  I  was,  face  and 
clothes  caked  with  yellow  mud,  my  hair  wild  and  matted,  my  hat  gone, 
and  in  my  full-grown  hands  a  tiny  tin  pail  of  sand,  as  if  I  had  been 
digging  all  night  with  a  tiny  tin  shovel  on  the  shore!  And  thus  to  appear 
in  the  decent  streets  of  Boston  of  a  Sunday  morning! 

"I  began  to  feel  like  a  hunted  criminal.  The  situation  was  serious,  or 
might  be,  and  rather  desperately  funny  at  its  best.  I  must  in  some  way 
have  shown  my  new  fears,  for  both  men  watched  me  more  sharply. 

"Suddenly,  as  we  were  nearing  the  outer  freight  yard,  the  train  slowed 
down  and  came  to  a  stop.  I  was  ready  to  jump,  but  I  had  no  chance.  They 
had  nothing  to  do,  apparently,  but  to  guard  me.  I  looked  at  my  watch 
again.  What  time  we  had  made!  It  was  only  six  o'clock,  with  a  whole  hour 
to  get  to  Cambridge. 

"But  I  didn't  like  this  delay.  Five  minutes — ten — went  by. 

"  'Gentlemen,'  I  began,  but  was  cut  short  by  an  express  train  coming 
past.  We  were  moving  again,  on — into  a  siding;  on — on  to  the  main 
track;  and  on  with  a  bump  and  a  crash  and  a  succession  of  crashes,  run- 
ning the  length  of  the  train;  on  at  a  turtle's  pace,  but  on,  when  the  fireman, 
quickly  jumping  for  the  bell  rope,  left  the  way  to  the  step  free,  and — the 
chance  had  come! 

"I  never  touched  the  step,  but  landed  in  the  soft  sand  at  the  side  of  the 
track,  and  made  a  line  for  the  yard  fence. 

"There  was  no  hue  or  cry.  I  glanced  over  my  shoulder  to  see  if  they  were 
after  me.  Evidently  their  hands  were  full,  and  they  didn't  know  I  had 

"But  I  had  gone;  and  was  ready  to  drop  over  the  high  board  fence, 
when  it  occurred  to  me  that  I  might  drop  into  a  policeman's  arms. 
Hanging  my  pail  in  a  splint  on  top  of  a  post,  I  peered  cautiously  over — a 
very  wise  thing  to  do  before  you  jump  a  high  board  fence.  There,  crossing 
the  open  square  toward  the  station,  was  a  big,  burly  fellow  with  a  club — 
looking  for  me. 

"I  flattened  for  a  moment,  when  someone  in  the  yard  yelled  at  me.  I 
preferred  the  policeman,  and,  grabbing  my  pail,  I  slid  over  to  the  street. 
The  policeman  moved  on  past  the  corner  of  the  station  out  of  sight.  The 
square  was  free,  and  yonder  stood  a  cab! 

"Time  was  flying  now.  Here  was  the  last  lap.  The  cabman  saw  me 
coming,  and  squared  away.  I  waved  a  paper  dollar  at  him,  but  he  only 
stared  the  more.  A  dollar  can  cover  a  good  deal,  but  I  was  too  much  for 


one  dollar.  I  pulled  out  another,  thrust  them  both  at  him,  and  dodged 
into  the  cab,  calling,  'Cambridge!' 

"He  would  have  taken  me  straight  to  the  police  station  had  I  not  said, 
'Harvard  College.  Professor  Agassiz's  house!  I've  got  eggs  for  Agassiz'; 
and  pushed  another  dollar  up  at  him  through  the  hole. 

"It  was  nearly  half  past  six. 

"  'Let  him  go!'  I  ordered.  "Here's  another  dollar  if  you  make  Agassiz's 
house  in  twenty  minutes.  Let  him  out;  never  mind  the  police!' 

"He  evidently  knew  the  police,  or  there  were  none  around  at  that  time 
on  a  Sunday  morning.  We  went  down  the  sleeping  streets  as  I  had  gone 
down  the  wood  roads  from  the  pond  two  hours  before,  but  with  the  rattle 
and  crash  now  of  a  fire  brigade.  Whirling  a  corner  into  Cambridge  Street, 
we  took  the  bridge  at  a  gallop,  the  driver  shouting  out  something  in 
Hibernian  to  a  pair  of  waving  arms  and  a  belt  and  brass  buttons. 

"Across  the  bridge  with  a  rattle  and  jolt  that  put  the  eggs  in  jeopardy, 
and  on  over  the  cobblestones,  we  went.  Half  standing,  to  lessen  the  jar,  I 
held  the  pail  in  one  hand  and  held  myself  in  the  other,  not  daring  to  let 
go  even  to  look  at  my  watch. 

"But  I  was  afraid  to  look  at  the  watch.  I  was  afraid  to  see  how  near  to 
seven  o'clock  it  might  be.  The  sweat  was  dropping  from  my  nose,  so  close 
was  I  running  to  the  limit  of  my  time. 

"Suddenly  there  was  a  lurch,  and  I  dived  forward,  ramming  my  head 
into  the  front  of  the  cab,  coming  up  with  a  rebound  that  landed  me 
across  the  small  of  my  back  on  the  seat,  and  sent  half  of  my  pail  of  eggs 
helter-skelter  over  the  floor. 

"We  had  stopped.  Here  was  Agassiz's  house;  and  without  taking  time 
to  pick  up  the  scattered  eggs  I  tumbled  out,  and  pounded  at  the  door. 

"No  one  was  astir  in  the  house.  But  I  would  stir  them.  And  I  did.  Right 
in  the  midst  of  the  racket  the  door  opened.  It  was  the  maid. 

"'Agassiz,'  I  gasped,  'I  want  Professor  Agassiz,  quick!'  And  I  pushed 
by  her  into  the  hall. 

"  'Go  'way,  sir.  I'll  call  the  police.  Professor  Agassiz  is  in  bed.  Go  'way, 

"  'Call  him — Agassiz — instantly,  or  I'll  call  him  myself.' 

"But  I  didn't;  for  just  then  a  door  overhead  was  flung  open,  a  great 
white-robed  figure  appeared  on  the  dim  landing  above,  and  a  quick  loud 
voice  called  excitedly: — 

"  'Let  him  in!  Let  him  inl  I  know  him.  He  has  my  turtle  eggs!' 

"And  the  apparition,  slipperless,  and  clad  in  anything  but  an  academic 
gown,  came  sailing  down  the  stairs, 


"The  maid  fled.  The  great  man,  his  arms  extended,  laid  hold  of  me  with 
both  hands,  and,  dragging  me  and  my  precious  pail  into  his  study,  with  a 
swift,  clean  stroke  laid  open  one  of  the  eggs,  as  the  watch  in  my  trembling 
hands  ticked  its  way  to  seven — as  if  nothing  unusual  were  happening  to 
the  history  of  the  world." 

"You  were  in  time,  then?"  I  said. 

"To  the  tick.  There  stands  my  copy  of  the  great  book.  I  am  proud  of  the 
humble  part  I  had  in  it." 


The  Aims  and  Methods  of  Science 


-^  knowledge — argument  and  experiment.  Argument  allows  us  to 
draw  conclusions,  and  may  cause  us  to  admit  the  conclusion;  but  it 
gives  no  proof,  nor  does  it  remove  doubt,  and  cause  the  mind  to  rest 
in  the  conscious  possession  of  truth,  unless  the  truth  is  discovered  by 
way  of  experience,  e.g.  if  any  man  who  had  never  seen  fire  were  to 
prove  by  satisfactory  argument  that  fire  burns  and  destroys  things,  the 
hearer's  mind  would  not  rest  satisfied,  nor  would  he  avoid  fire;  until  by 
putting  his  hand  or  some  combustible  thing  into  it,  he  proved  by  actual 
experiment  what  the  argument  laid  down;  but  after  the  experiment  has 
been  made,  his  mind  receives  certainty  and  rests  in  the  possession  of 
truth  which  could  not  be  given  by  argument  but  only  by  experience. 
And  this  is  the  case  even  in  mathematics,  where  there  is  the  strongest 
demonstration.  For  let  anyone  have  the  clearest  demonstration  about  an 
equilateral  triangle  without  experience  of  it,  his  mind  will  never  lay 


hold  of  the  problem  until  he  has  actually  before  him  the  intersecting 
circles  and  the  lines  drawn  from  the  point  of  section  to  the  extremities 
of  a  straight  line. 





I  am  glad  to  see  you  before  me,  a  flourishing  band  of  young  people 
who  have  chosen  applied  science  as  a  profession. 

I  could  sing  a  hymn  of  praise  with  the  refrain  of  the  splendid  progress 
in  applied  science  that  we  have  already  made,  and  the  enormous  further 
progress  that  you  will  bring  about.  We  are  indeed  in  the  era  and  also 
in  the  native  land  of  applied  science. 

But  it  lies  far  from  my  thought  to  speak  in  this  way.  Much  more,  I  am 
reminded  in  this  connection  of  the  young  man  who  had  married  a  not 
very  attractive  wife  and  was  asked  whether  or  not  he  was  happy.  He 
answered  thus:  "If  I  wished  to  speak  the  truth,  then  I  would  have  to 

So  it  is  with  me.  Just  consider  a  quite  uncivilized  Indian,  whether  his 
experience  is  less  rich  and  happy  than  that  of  the  average  civilized 
man.  I  hardly  think  so.  There  lies  a  deep  meaning  in  the  fact  that  the 
children  of  all  civilized  countries  are  so  fond  of  playing  "Indians." 

Why  does  this  magnificent  applied  science,  which  saves  work  and 
makes  life  easier,  bring  us  so  little  happiness?  The  simple  answer 
runs — because  we  have  not  yet  learned  to  make  a  sensible  use  of  it. 

In  war,  it  serves  that  we  may  poison  and  mutilate  each  other.  In 
peace  it  has  made  our  lives  hurried  and  uncertain.  Instead  of  freeing  us 
in  great  measure  from  spiritually  exhausting  labor,  it  has  made  men  into 
slaves  of  machinery,  who  for  the  most  part  complete  their  monotonous 
long  day's  work  with  disgust,  and  must  continually  tremble  for  their 
poor  rations. 

You  will  be  thinking  that  the  old  man  sings  an  ugly  song.  I  do  it,  how- 
ever, with  a  good  purpose,  in  order  to  point  out  a  consequence. 


It  is  not  enough  that  you  should  understand  about  applied  science 
in  order  that  your  work  may  increase  man's  blessings.  Concern  for  man 
himself  and  his  fate  must  always  form  the  chief  interest  of  all  technical 
endeavors,  concern  for  the  great  unsolved  problems  of  the  organization 
cf  labor  and  the  distribution  of  goods — in  order  that  the  creations  of  our 
mind  shall  be  a  blessing  and  not  a  curse  to  mankind.  Never  forget  this 
in  the  midst  of  your  diagrams  and  equations. 


From  Stars  and  Atoms 

themselves  wings.  Daedalus  flew  safely  through  the  middle  air  and 
was  duly  honored  on  his  landing.  Icarus  soared  upwards  to  the  sun  till 
the  wax  melted  which  bound  his  wings  and  his  flight  ended  in  fiasco. 
In  weighing  their  achievements,  there  is  something  to  be  said  for 
Icarus.  The  classical  authorities  tell  us  that  he  was  only  "doing  a  stunt," 
but  I  prefer  to  think  of  him  as  the  man  who  brought  to  light  a  serious 
constructional  defect  in  the  flying  machines  of  his  day.  So,  too,  in  science, 
cautious  Daedalus  will  apply  his  theories  where  he  feels  confident  they 
will  safely  go;  but  by  his  excesses  of  caution  their  hidden  weaknesses 
remain  undiscovered.  Icarus  will  strain  his  theories  to  the  breaking 
point  till  the  weak  points  gape.  For  the  mere  adventure?  Perhaps  partly; 
that  is  human  nature.  But  if  he  is  destined  not  yet  to  reach  the  sun  and 
solve  finally  the  riddle  of  its  constitution  we  may  hope  at  least  to 
learn  from  his  journey  some  hints  to  build  a  better  machine. 







my  country?  First  of  all,  sequence,  consequence  and  again  con- 
sequence. In  gaining  knowledge  you  must  accustom  yourself  to  the 
strictest  sequence.  You  must  be  familiar  with  the  very  groundwork  of 
science  before  you  try  to  climb  the  heights.  Never  start  on  the  "next" 
before  you  have  mastered  the  "previous."  Do  not  try  to  conceal  the 
shortcomings  of  your  knowledge  by  guesses  and  hypotheses.  Accustom 
yourself  to  the  roughest  and  simplest  scientific  tools.  Perfect  as  the  wing 
of  a  bird  may  be,  it  will  never  enable  the  bird  to  fly  if  unsupported  by 
the  air.  Facts  are  the  air  of  science.  Without  them  the  man  of  science 
can  never  rise.  Without  them  your  theories  are  vain  surmises.  But  while 
you  are  studying,  observing,  experimenting,  do  not  remain  content  with 
the  surface  of  things.  Do  not  become  a  mere  recorder  of  facts,  but  try 
to  penetrate  the  mystery  of  their  origin.  Seek  obstinately  for  the  laws  that 
govern  them.  And  then—modesty.  Never  think  you  know  all.  Though 
others  may  flatter  you,  retain  the  courage  to  say,  "I  am  ignorant."  Never 
be  proud.  And  lastly,  science  must  be  your  passion.  Remember  that  science 
claims  a  man's  whole  life.  Had  he  two  lives  they  would  not  suuice. 
Science  demands  an  undivided  allegiance  from  its  followers.  Li  your 
work  and  in  your  research  there  must  always  be  passion. 


just  as  the  scientist's  objective  search  for  truth  will  outlive  all  the 
regimented  thinking  of  totalitarianism.  Temporarily  eclipsed,  the  proud 


names  of  Paris,  Strasbourg,  Prague,  Louvain,  Warsaw,  Leyden,  as  well 
as  Heidelberg  and  Leipsic  and  Berlin,  will  once  again  stand  for  the 
quest  for  truth;  once  again  will  they  be  centers  of  candid  and  fearless 
thinking—homes  of  the  untrammeled  and  unafraid,  where  there  is  liberty 
to  learn,  opportunity  to  teach  and  power  to  understand. 

The  task  which  faces  all  institutions  concerned  with  the  advance 
of  knowledge  is  not  only  to  keep  this  faith  alive  but  to  make  certain, 
as  far  as  they  can,  that  the  streams  of  culture  and  learning,  wherever 
they  may  be  located  or  however  feebly  they  may  now  flow,  shall  not 
be  blocked.  .  .  . 

...  If  we  are  to  have  a  durable  peace  after  the  war,  if  out  of  the 
Wreckage  of  the  present,  a  new  kind  of  cooperative  life  is  to  be  built 
on  a  global  scale,  the  part  that  science  and  advancing  knowledge  will 
play  must  not  be  overlooked.  For  although  wars  arid  economic  rivalries 
may  for  longer  or  shorter  periods  isolate  nations  and  split  them  up  into 
separate  units,  the  process  is  never  complete  because  the  intellectual 
life  of  the  world,  as  far  as  science  and  learning  are  concerned,  is  definitely 
internationalized,  and  whether  we  wish  it  or  not  an  indelible  pattern 
of  unity  has  been  woven  into  the  society  of  mankind. 

There  is  not  an  area  of  activity  in  which  this  cannot  be  illustrated.  An 
American  soldier,  wounded  on  a  battlefield  in  the  Far  East,  owes  his  life 
to  the  Japanese  scientist,  Kitasato,  who  isolated  the  bacillus  of  tetanus. 
A  Russian  soldier,  saved  by  a  blood  transfusion,  is  indebted  to  Land- 
steiner,  an  Austrian.  A  German  soldier  is  shielded  from  typhoid  fever 
with  the  help  of  a  Russian,  MetchnikofJ.  A  Dutch  marine  in  the  East 
Indies  is  protected  from  malaria  because  of  the  experiments  of  an 
Italian,  Grassi;  while  a  British  aviator  in  North  Africa  escapes  death 
from  surgical  infection  because  a  Frenchman,  Pasteur,  and  a  German, 
Koch,  elaborated  a  new  technique. 

In  peace,  as  in  war,  we  are  all  of  us  the  beneficiaries  of  contributions 
to  knowledge  made  by  every  nation  in  the  world.  Our  children  are 
guarded  from  diphtheria  by  what  a  Japanese  and  a  German  did,  they 
are  protected  from  smallpox  by  an  Englishman's  work;  they  are  saved 
from  rabies  because  of  a  Frenchman;  they  are  cured  of  pellagra  through 
the  researches  of  an  Austrian.  From  birth  to  death,  they  are  surrounded 
by  an  invisible  host — the  spirits  of  men  who  never  thought  in  terms  of 
flags  or  boundary  lines  and  who  never  served  a  lesser  loyalty  than  the 
welfare  of  mankind.  The  best  that  every  individual  or  group  has 
produced  anywhere  in  the  world  has  always  been  available  to  serve  the 
race  of  men,  regardless  of  nation  or  color. 

What  is  true  of  the  medical  sciences  is  true  of  the  other  sciences. 


Whether  it  is  mathematics  or  chemistry,  whether  it  is  bridges  or  auto- 
mobiles or  a  new  device  for  making  cotton  cloth  or  a  cyclotron  for 
studying  atomic  structure,  ideas  cannot  be  hedged  in  behind  geographical 
barriers.  Thought  cannot  be  nationalized.  The  fundamental  unity  of 
civilization  is  the  unity  of  its  intellectual  life. 

There  is  a  real  sense,  therefore,  in  which  the  things  that  divide  us  are 
trivial  as  compared  with  the  things  that  unite  us.  The  foundations  of  a 
cooperative  world  have  already  been  laid.  It  is  not  as  if  we  were  starting 
from  the  beginning.  For  at  least  three  hundred  years,  the  process  has 
been  at  work,  until  today  the  cornerstones  of  society  are  the  common 
interests  that  relate  to  the  welfare  of  all  men  everywhere. 

In  brief,  the  age  of  distinct  human  societies,  indifferent  to  the  fate  of 
one  another,  has  passed  forever;  and  the  great  task  that  will  confront 
us  after  the  war  is  to  develop  for  the  community  of  nations  new  areas  and 
techniques  of  cooperative  action  which  will  fit  the  facts  of  our  twentieth 
century  interdependence.  We  need  rallying  points  of  unity,  centers  around 
which  men  of  different  cultures  and  faiths  can  combine,  defined  fields  of 
need,  or  goals  of  effort,  in  which  by  pooling  its  brains  and  resources,  the 
human  race  can  add  to  its  own  well-being.  Only  as  we  begin  to  build, 
brick  by  brick,  in  these  areas  of  common  interest  where  cooperation  is 
possible  and  the  results  are  of  benefit  to  all,  can  we  erect  the  ultimate 
structure  of  a  united  society. 

A  score  of  inviting  areas  for  this  kind  of  cooperation  deserve  explo- 
ration. Means  must  be  found  by  which  the  potential  abundance  of  the 
world  can  be  translated  into  a  more  equitable  standard  of  living.  Mini- 
mum standards  of  food,  clothing  and  shelter  should  be  established.  The 
new  science  of  nutrition,  slowly  coming  to  maturity,  should  be  expanded 
on  a  world-wide  scale.  The  science  of  agriculture  needs  development, 
not  only  in  our  own  climate  but  particularly  in  the  tropic  and  sub- 
tropic  zones.  With  all  their  brilliant  achievements,  the  medical  sciences 
are  in  their  infancy.  Public  health  stands  at  the  threshold  of  new 
possibilities.  Physics  and  chemistry  have  scarcely  started  their  contri- 
butions to  the  happiness  and  comfort  of  human  living.  Economics  and 
political  science  are  only  now  beginning  to  tell  us  in  more  confident 
tones  how  to  make  this  world  a  home  to  live  in  instead  of  a  place  to 
fight  and  freeze  and  starve  in. 






ago,  Nicholas  Copernicus  received  on  his  death  bed  the  first  copy  of  his  im- 
mortal book,  De  Revolutionibus  Orbium  Coelestium  (Concerning  the  Revo- 
lutions of  the  Heavenly  Bodies),  in  which  he  expressed  his  belief  that  the 
earth  moves  around  the  sun.  A  few  hours  later  he  closed  his  eyes  on  a 
medieval  world  that  still  believed  in  Ptolemy's  geocentric  universe. 

Sixty-seven  years  later,  in  1610,  Galileo  Galilei  watched  four  small  bodies 
which  appeared  in  the  field  of  his  telescope.  Night  after  night  he  observed 
them  as  they  moved  around  the  planet  Jupiter.  Here  was  a  miniature  solar 
system  similar  to  our  own.  Here  was  proof  of  the  Copernican  theory.  Thus, 
one  of  the  greatest  revolutions  in  the  history  of  the  human  race  took  place. 
Man  was  no  longer  the  center  of  the  world;  he  had  assumed  a  subordinate 
place  in  a  larger  universe. 

In  the  following  pages  this  story  of  Copernicus  and  Galileo  is  told  in  their 
own  words.  As  we  read,  some  of  the  excitement  and  wonder  which  they 
must  have  felt  comes  to  us  across  the  centuries. 

Since  that  day,  our  knowledge  of  astronomy  has  greatly  increased.  We 
know  more  about  the  planets;  much  more  about  the  composition  and  even 
the  internal  constitution  of  the  stars;  and  we  have  discovered  realms  far  be- 
yond the  range  of  Galileo's  little  telescope.  This  Orderly  Universe  extends 
from  OUT  familiar  satellite,  the  moon,  to  those  exterior  galaxies  which  are 
visible  only  in  the  largest  telescopes.  To  tell  us  about  it,  we  chose  Forest  Ray 
Moulton,  who  with  T.  C.  Chamberlin  is  responsible  for  the  modern  theory 
that  the  solar  system  was  formed  by  the  passage  of  a  star  near  our  own  sun. 
His  description  is  an  astronomical  education  in  brief — a  bird's-eye  view  ot 
modern  astronomy. 



As  man  loolcs  at  the  planets  and  shrinks  in  size  before  those  distant  gal- 
axies, it  is  natural  that  he  should  ask  Is  There  Life  on  Other  Worlds?  As 
Sir  James  Jeans  explains,  science  has  its  answer,  based  on  facts  of  atmosphere, 
temperature  and  mathematical  ca/culation. 

Life  as  we  know  it  probably  does  not  exist  elsewhere  in  the  solar  system.  It 
may  appear  somewhere  in  our  galaxy,  or  in  some  other  galaxy  outside  the 
Milky  Way.  We  do  not  know,  although  we  know  much  about  these  ex- 
terior systems.  In  the  field  of  external  galaxies  numerous  recent  develop- 
ments have  taken  place.  In  The  Milky  Way  and  Beyond,  Sir  Arthur  Edding- 
ton,  who  is  responsible  for  many  of  these  developments,  tells  about  them  and 
explains  why  he  believes  the  universe  is  expanding.  It  is  a  fascinating  hypoth- 
esis, though  there  is  disagreement  among  astronomers  as  to  its  correctness. 
When  the  2OO-inch  telescope  is  finished,  the  problem  may  be  solved. 

B.    THE    EARTH 

From  outer  space  to  A  Young  Man  Looking  at  Rocks  is  a  long  jump  to 
more  familiar  ground.  It  is  easier  to  contemplate  the  sculptured  heart  of  a 
fossil  than  the  arms  of  a  spiral  nebula.  Yet  for  that  very  reason,  we  are  apt 
to  take  the  "commonest  things"  for  granted.  We  forget  that  rocks,  like 
everything  else,  have  a  history.  Old  rocks  hold  the  key  to  the  age  of  the 
earth;  younger  ones  the  clue  to  the  origin  of  species.  With  Hugh  Miller 
we  observe  the  history  of  the  earth's  crust  spread  before  us,  in  massive  blocks 
of  gneiss  and  hornblende  and  sedimentary  beds  of  sandstone  and  shale.  It  is 
charming  autobiography  from  one  of  the  classics  of  geology. 

In  the  different  types  of  rocks,  Sir  Archibald  Geike  can  trace  the  story  of 
bygone  ages.  In  the  remarkable  Geological  Change,  this  famous  nineteenth 
century  scientist  describes  the  fundamentals  of  geology.  He  tells  of  the 
rhythmic  cycles  caused  by  alternate  erosion  and  uplifting  of  land.  He  tells  of 
the  catastrophic  changes  which  give  rise  to  Earthquakes  described  by  Father 
Macelwane,  or  ferocious  volcanic  eruptions  like  that  which  doomed  forty 
thousand  lives  in  St.  Pierre,  ironically  saving  the  one  man  who  was  in  /ail. 

In  the  organic  remains,  the  fossils,  laid  down  in  stratified  rock,  Geike 
discerns  forms  now  extinct — the  ferns  and  conifers  of  which  Peattie  writes 
in  a  later  part;  the  scales  of  fishes  found  by  Hugh  Miller;  the  remains  of 
dinosaurs  that  once  roamed  the  earth;  even  the  fragments  of  prehistoric  man, 
the  missing  links  about  which  you  may  read  in  Part  Five. 

Finally,  like  Paul  B.  Sears  in  Man,  Maker  of  Wilderness,  Geike  watches 
the  effects  of  erosion  on  the  land.  Here  is  a  clue  to  the  decay  of  those  civili- 
zations which  permit  man  to  take  everything  from  the  earth,  giving  noth- 
ing in  return. 

We  have  removed  from  Geological  Change  a  section  on  the  celebrated 
nineteenth  century  controversy  between  the  physicists  and  the  geologists 
about  the  age  of  the  earth.  The  age  set  by  the  physicists,  led  by  Lord  Kelvin, 
was  far  too  short  for  the  very  slow  and  gradual  changes  the  geologists 


envisaged.  That  controversy  was  settled  by  the  discovery  of  radium.  It's  dis- 
integration furnished  a  source  of  energy  the  physicists  had  not  taken  into 
their  calculations.  And  its  slow  change  into  a  unique  type  of  lead  within  a 
set  period  has  furnished  a  valuable  new  geological  clock.  Examination  of 
radioactive  substances  in  the  oldest  rocks  now  leads  us  to  assign  a  period  of 
about  1,500,000,000  to  2,000,000,000  years  as  the  age  of  the  earth. 

If  we  would  understand  the  wind  and  the  rain,  we  must  know  What 
Makes  the  Weather.  In  aviation  and  agriculture  and  a  thousand  other  activi- 
ties, it  is  a  problem  of  vital  importance.  In  long  range  history,  it  may  mean 
climatic  change  that  can  alter  the  surface  of  a  hemisphere.  Here  are  the 
modern  theories  about  cold  fronts  and  air  masses.  Here  are  the  ideas  which 
help  the  weatherman  become  a  successful  prophet. 


In  1642,  when  Galileo  died  an  old  and  disillusioned  man,  he  had  already 
learned  a  great  deal  about  the  mathematical  meaning  of  motion.  But  he  still 
did  not  understand  why  the  planets  moved  around  the  sun.  He  could  not 
know  that  in  that  same  year  a  baby  would  be  born  who  would  create  a  world 
conforming  to  both  mathematical  and  physical  law. 

On  Christmas  Day,  1642,  Isaac  Newton  was  born  in  the  village  of  Wools- 
thorpe  in  Lincolnshire,  a  premature,  frail  baby,  the  posthumous  son  of  a 
yoeman  farmer.  Despite  expectations  to  the  contrary,  he  lived,  and  became  the 
greatest  scientist  in  history.  He  was  to  discover  the  law  of  gravitation,  the 
laws  of  motion,  the  principles  of  optics,  the  composite  nature  of  light,  and 
with  Leibnitz  to  invent  the  calculus.  He  of  course  owed  a  great  debt  to 
Galileo  and  to  two  other  astronomers  who  lived  in  this  same  extraordinary 
period:  Tycho  Brahe,  who  first  recorded  accurately  the  motions  of  the  plan- 
ets; and  Johann  Kepler  whose  laws  of  planetary  motion  showed  how  these 
planets  moved  with  relation  to  their  central  sun.  On  the  foundations  laid  by 
these  three,  Newton  built  a  conception  of  the  world  and  the  forces  that 
guide  it  that  was  destined  to  hold  undisputed  place  until  the  beginning  of 
the  twentieth  century,  and  even  at  that  distant  date  to  undergo  but  minor 

Newtoniana  tells  us  something  of  the  man;  while  Discoveries  gives  us  all 
too  brief  glimpses  of  the  work  that  made  him  what  he  was. 

The  Physical  Laws  of  the  world  are  not  easy  to  comprehend.  Mathematics, 
physics  and  chemistry  are  so  bound  up  with  mysterious  symbolism,  not  diffi- 
cult in  itself  but  unintelligible  to  those  who  have  not  learned  its  secret, 
that  words  cannot  give  their  full  meaning.  Yet  meaning  they  do  have,  even 
for  the  layman.  Much  of  it  is  conveyed  in  the  selections  that  follow. 

First,  let  us  consider  mathematics,  the  foundation  of  physical  law,  the 
indispensable  tool  of  the  scientist.  It  transforms  indefinite  thoughts  into 
specific  theories.  With  its  advance  has  come  the  advance  of  civilization.  In 


remote  ages  primitive  man  learned  to  count;  later  to  measure;  finally  to  cal- 
culate. So  we  come  to  the  modern  world  of  science,  where  man  must  be  a 
"calculating  animal"  if  he  is  to  understand  physical  and  even  biological 
science.  Hogben  tells  something  of  the  story  in  Mathematics,  the  Mirror  of 

From  mathematics  we  turn  to  physics.  But  before  we  do  so,  let  us  consider 
the  Experiments  and  Ideas  of  that  protean  American  Ben  Franklin.  He  is 
best  known  for  his  work  with  electricity,  with  kites  and  lightning  rods.  Few 
remember  his  bifocal  glasses,  his  discovery  of  the  origin  of  northeast  storms, 
his  extraordinary  prophecy  of  aerial  invasion. 

In  physics,  we  run  squarely  against  one  of  the  fundamental  scientific  prob- 
lems of  the  century:  what  goes  on  inside  the  atom?  In  Exploring  the  Atom, 
Sir  James  Jeans  describes  this  strange  world  which  all  of  us  have  heard  about 
yet  few  understand.  He  shows  how  our  nineteenth  century  concept  of  the 
atom  as  a  sort  of  indestructible  brick  has  been  changed  completely;  he 
makes  the  new  picture  of  the  atom  really  clear.  And  in  doing  so,  he  gives  us 
the  basic  knowledge  which  we  must  have  to  understand  atomic  fission  and 
the  atomic  bomb. 

E.  O.  Lawrence,  the  California  scientist  who  developed  the  world-famous 
cyclotron,  has  become  one  of  the  leaders  in  research  on  atomic  fission.  Long 
before  our  entrance  into  the  war,  his  famous  machine  had  "smashed  the 
atom/'  In  Touring  the  Atomic  World,  Henry  Schacht  gives  a  description  of 
his  technique  which  the  layman  can  understand.  Not  so  long  after  this 
article  was  written,  wartime  secrecy  shrouded  the  work  of  Lawrence  and 
other  nuclear  physicists.  The  veil  was  lifted  when  a  bomb  exploded  over 
Hiroshima.  It  is  interesting  to  note  how  much  research  went  into  the  subject, 
long  before  its  military  implications  were  thought  of. 

The  first  clue  to  the  breaking  up  of  the  atomic  nucleus  was  given  by  those 
radioactive  substances  which  disintegrate  spontaneously.  Jeans  and  Schacht 
have  told  us  something  about  them;  and  now  we  come  to  the  work  of  that 
extraordinary  woman,  Marie  Curie,  who  kept  house,  brought  up  a  family, 
and  discovered  radium.  The  Discovery  of  Radium  is  a  story  which  gains  new 
meaning  when  it  is  related  to  the  course  of  modern  physics. 

It  is  impossible  to  think  of  the  question  of  matter  apart  from  the  equally 
fundamental  one  of  energy.  "Almost  every  problem  of  living  turns  out  in  the 
last  analysis  to  be  a  problem  of  the  control  of  energy/'  writes  George  Russell 
Harrison  of  M.  I.  T.  In  The  Taming  of  Energy,  he  tells  us  something  of  how 
the  various  forms  are  interrelated.  The  question  is  complicated  by  Einstein, 
who  says  that  matter  and  energy  are  related  according  to  mathematical  law. 
That  relationship  is  deep  water  indeed,  as  is  all  relativity  theory.  Yet  in  Space, 
Time  and  Einstein,  Dr.  Heyl,  the  man  who  weighed  the  earth,  says  interest- 
ing things  about  relativity  which  are  not  too  difficult  for  the  informed  lay- 


As  physics  and  chemistry  continue  to  advance,  it  becomes  harder  to  decide 
where  one  begins  and  the  other  ends.  In  the  eighteenth  century  when 
Lavoisier,  "Father  of  Modern  Chemistry/'  died  on  the  guillotine  because  the 
French  Revolution  had  "no  need  for  scientists/'  there  was  little  connection. 
In  the  nineteenth,  when  Mendeteef  set  up  his  periodic  table,  the  gulf  re- 
mained. Basic  work  dealt  with  discovering  and  arranging  the  elements.  In 
the  periodic  table,  Mendeteef  arranged  the  elements  according  to  their  atomic 
weights  in  somewhat  the  same  way  that  the  days  of  the  month  are  arranged 
on  a  calendar.  When  this  was  done,  the  elements  in  any  vertical  column 
(the  Sundays  or  Fridays)  resembled  one  another  in  basic  chemical  properties. 
As  many  elements  had  not  been  discovered,  it  was  necessary  to  leave  gaps  in 
the  table.  He  prophesied  that  some  day  these  gaps  would  be  filled  by  ele- 
ments which  were  then  unknown,  and  this  is  exactly  what  has  happened. 

There  is  another  aspect  of  chemistry  which  is  perhaps  of  greater  interest 
to  the  lay  reader — its  application  to  everyday  life.  On  chemical  reactions 
depend  practically  all  industrial  processes  of  the  present  day.  On  the  re- 
arrangement of  atoms  and  molecules  of  substances  which  occur  in  nature, 
depends  the  creation  of  the  synthetics  which  are  becoming  an  inseparable 
part  of  our  lives.  One  subject  is  discussed  by  the  director  of  the  Du  Pont 
laboratories  in  The  Foundations  of  Chemical  Industry;  the  other  by  the 
Science  Editor  of  the  New  York  Times  in  The  Chemical  Revolution. 

Finally  comes  the  all-absorbing  question  of  the  war.  Many  weapons  of 
scientific  warfare  are  held  in  greatest  secrecy  by  various  powers.  But  many 
others  can  be  discussed  because  they  are  known  to  all. 

In  Jets  Power  Future  Flying,  Watson  Davis,  the  Director  of  Science 
Service,  the  country's  leading  organization  for  the  general  dissemination  of 
scientific  information,  describes  the  various  techniques  whereby  jet  propul- 
sion is  revolutionizing  aviation.  In  Science  in  War  and  After,  Dr.  Harrison 
tells  us  about  tanks  that  are  tougher,  aerial  photography  that  sees  farther, 
naval  guns  that  shoot  straighter,  and  radio  locators  that  see  where  human 
eyes  are  useless. 


A  Theory  that  the  Earth  Moves  Around  the  Sun 


From  Concerning  the  Revolutions  of  the  Heavenly  Bodies 



JL  spherical;  partly  because  this  form,  being  a  complete  whole,  needing 
no  joints,  is  the  most  perfect  of  all;  partly  because  it  constitutes  the  most 
spacious  form,  which  is  thus  best  suited  to  contain  and  retain  all  things; 
or  also  because  all  discrete  parts  of  the  world,  I  mean  the  sun,  the  moon 
and  the  planets,  appear  as  spheres;  or  because  all  things  tend  to  assume 
the  spherical  shape,  a  fact  which  appears  in  a  drop  of  water  and  in  other 
fluid  bodies  when  they  seek  of  their  own  accord  to  limit  themselves. 
Therefore  no  one  will  doubt  that  this  form  is  natural  for  the  heavenly 


That  the  earth  is  likewise  spherical  is  beyond  doubt,  because  it  presses 
from  all  sides  to  its  center.  Although  a  perfect  sphere  is  not  immediately 
recognized  because  of  the  great  height  of  the  mountains  and  the  depres- 
sion of  the  valleys,  yet  this  in  no  wise  invalidates  the  general  spherical 
form  of  the  earth.  This  becomes  clear  in  the  following  manner:  To 
people  who  travel  from  any  place  to  the  North,  the  north  pole  of  the 
daily  revolution  rises  gradually,  while  the  south  pole  sinks  a  like  amount. 
Most  of  the  stars  in  the  neighborhood  of  the  Great  Bear  appear  not  to 
set,  and  in  the  South  some  stars  appear  no  longer  to  rise.  Thus  Italy 
does  not  see  Canopus,  which  is  visible  to  the  Egyptians.  And  Italy  sees 
the  outermost  star  of  the  River,  which  is  unknown  to  us  of  a  colder  zone. 
On  the  other  hand,  to  people  who  travel  toward  the  South,  these  stars 
rise  higher  in  the  heavens,  while  those  stars  which  are  higher  to  us 



become  lower.  Therefore,  it  is  plain  that  the  earth  is  included  between 
the  poles  and  is  spherical.  Let  us  add  that  the  inhabitants  of  the  East  do 
not  see  the  solar  and  lunar  eclipses  that  occur  in  the  evening,  and  people 
who  live  in  the  West  do  not  see  eclipses  that  occur  in  the  morning,  while 
those  living  in  between  see  the  former  later,  and  the  latter  earlier. 

That  even  the  water  has  the  same  shape  is  observed  on  ships,  in  that 
the  land  which  can  not  be  seen  from  the  ship  can  be  spied  from  the  tip 
of  the  mast.  And,  conversely,  when  a  light  is  put  on  the  tip  of  the  mast, 
it  appears  to  observers  on  land  gradually  to  drop  as  the  ship  recedes  until 
the  light  disappears,  seeming  to  sink  in  the  water.  It  is  clear  that  the 
water,  too,  in  accordance  with  its  fluid  nature,  is  drawn  downwards,  just 
as  is  the  earth,  and  its  level  at  the  shore  is  no  higher  than  its  convexity 
allows.  The  land  therefore  projects  everywhere  only  as  far  above  the 
ocean  as  the  land  accidentally  happens  to  be  higher.  .  .  . 


Since  it  has  already  been  proved  that  the  earth  has  the  shape  of  a 
sphere,  I  insist  that  we  must  investigate  whether  from  its  form  can  be 
deduced  a  motion,  and  what  place  the  earth  occupies  in  the  universe. 
Without  this  knowledge  no  certain  computation  can  be  made  for  the 
phenomena  occurring  in  the  heavens.  To  be  sure,  the  great  majority  of 
writers  agree  that  the  earth  is  at  rest  in  the  center  of  the  universe,  so  that 
they  consider  it  unbelievable  and  even  ridiculous  to  suppose  the  contrary. 
Yet,  when  one  weighs  the  matter  carefully,  he  will  see  that  this  question 
is  not  yet  disposed  of,  and  for  that  reason  is  by  no  means  to  be  considered 
unimportant.  Every  change  of  position  which  is  observed  is  due  either 
to  the  motion  of  the  observed  object  or  of  the  observer,  or  to  motions, 
naturally  in  different  directions,  of  both;  for  when  the  observed  object 
and  the  observer  move  in  the  same  manner  and  in  the  same  direction, 
then  no  motion  is  observed.  Now  the  earth  is  the  place  from  which  we 
observe  the  revolution  of  the  heavens  and  where  it  is  displayed  to  our 
eyes.  Therefore,  if  the  earth  should  possess  any  motion,  the  latter  would 
be  noticeable  in  everything  that  is  situated  outside  of  it,  but  in  the 
opposite  direction,  just  as  if  everything  were  traveling  past  the  earth. 
And  of  this  nature  is,  above  all,  the  daily  revolution.  For  this  motion 
seems  to  embrace  the  whole  world,  in  fact,  everything  that  is  outside  of 
the  earth,  with  the  single  exception  of  the  earth  itself.  But  if  one  should 
admit  that  the  heavens  possess  none  of  this  motion,  but  that  the  earth 
rotates  from  west  to  east;  and  if  one  should  consider  this  seriously  with 
respect  to  the  seeming  rising  and  setting  of  the  sun,  of  the  moon  and 


the  stars;  then  one  would  find  that  it  is  actually  true.  Since  the  heavens 
which  contain  and  retain  all  things  are  the  common  home  of  all  things, 
it  is  not  at  once  comprehensible  why  a  motion  is  not  rather  ascribed  to 
the  thing  contained  than  to  the  containing,  to  the  located  rather  than  to 
the  locating.  This  opinion  was  actually  held  by  the  Pythagoreans  Heraklid 
and  Ekphantus  and  the  Syracusean  Nicetas  (as  told  by  Cicero),  in  that 
they  assumed  the  earth  to  be  rotating  in  the  center  of  the  universe.  They 
were  indeed  of  the  opinion  that  the  stars  set  due  to  the  intervening  of 
the  earth,  and  rose  due  to  its  receding.  .  .  . 


It  is  claimed  that  the  earth  is  at  rest  in  the  center  of  the  universe  and 
that  this  is  undoubtedly  true.  But  one  who  believes  that  the  earth  rotates 
will  also  certainly  be  of  the  opinion  that  this  motion  is  natural  and  not 
violent.  Whatever  is  in  accordance  with  nature  produces  effects  which 
are  the  opposite  of  what  happens  through  violence.  Things  upon  wrhich 
violence  or  an  external  force  is  exerted  must  become  annihilated  and 
cannot  long  exist.  But  whatever  happens  in  the  course  of  nature  remains 
in  good  condition  and  in  its  best  arrangement.  Without  cause,  therefore, 
Ptolemy  feared  that  the  earth  and  all  earthly  things  if  set  in  rotation 
would  be  dissolved  by  the  action  of  nature,  for  the  functioning  of  nature 
is  something  entirely  different  from  artifice,  or  from  that  which  could 
be  contrived  by  the  human  mind.  But  why  did  he  not  fear  the  same,  and 
indeed  in  much  higher  degree,  for  the  universe,  whose  motion  would 
have  to  be  as  much  more  rapid  as  the  heavens  are  larger  than  the  earth? 
Or  have  the  heavens  become  infinite  just  because  they  have  been  removed 
from  the  center  by  the  inexpressible  force  of  the  motion;  while  otherwise, 
if  they  were  at  rest,  they  would  collapse?  Certainly  if  this  argument 
were  true  the  extent  of  the  heavens  would  become  infinite.  For  the  more 
they  were  driven  aloft  by  the  outward  impulse  of  the  motion,  the  more 
rapid  would  the  motion  become  because  of  the  ever  increasing  circle 
which  it  would  have  to  describe  in  the  space  of  24  hours;  and,  con- 
versely, if  the  motion  increased,  the  immensity  of  the  heavens  would  also 
increase.  Thus  velocity  would  augment  size  into  infinity,  and  size, 
velocity.  But  according  to  the  physical  law  that  the  infinite  can  neither 
be  traversed,  nor  can  it  for  any  reason  have  motion,  the  heavens  would, 
however,  of  necessity  be  at  rest. 

But  it  is  said  that  outside  of  the  heavens  there  is  no  body,  nor  place, 
nor  empty  space,  in  fact,  that  nothing  at  all  exists,  and  that,  therefore, 
there  is  no  space  in  which  the  heavens  could  expand;  then  it  is  really 
strange  that  something  could  be  enclosed  by  nothing.  If,  however,  the 
heavens  were  infinite  and  were  bounded  only  by  their  inner  concavity, 


then  we  have,  perhaps,  even  better  confirmation  that  there  is  nothing 
outside  of  the  heavens,  because  everything,  whatever  its  size,  is  within 
them;  but  then  the  heavens  would  remain  motionless.  The  most  impor- 
tant argument,  on  which  depends  the  proof  of  the  finiteness  of  the 
universe,  is  motion.  Now,  whether  the  world  is  finite  or  infinite,  we  will 
leave  to  the  quarrels  of  the  natural  philosophers;  for  us  remains  the 
certainty  that  the  earth,  contained  between  poles,  is  bounded  by  a  spher- 
ical surface.  Why  should  we  hesitate  to  grant  it  a  motion,  natural  and 
corresponding  to  its  form;  rather  than  assume  that  the  whole  world, 
whose  boundary  is  not  known  and  cannot  be  known,  moves?  And  why 
are  we  not  willing  to  acknowledge  that  the  appearance  of  a  daily  revolu- 
tion belongs  to  the  heavens,  its  actuality  to  the  earth?  The  relation  is 
similar  to  that  of  which  Virgil's  /Eneas  says:  "We  sail  out  of  the  harbor, 
and  the  countries  and  cities  recede."  For  when  a  ship  is  sailing  along 
quietly,  everything  which  is  outside  of  it  will  appear  to  those  on  board 
to  have  a  motion  corresponding  to  the  movement  of  the  ship,  and  the 
voyagers  are  of  the  erroneous  opinion  that  they  with  all  that  they  have 
with  them  are  at  rest.  This  can  without  doubt  also  apply  to  the  motion 
of  the  earth,  and  it  may  appear  as  if  the  whole  universe  were  revolving 


.  .  .  Since  nothing  stands  in  the  way  of  the  movability  of  the  earth, 
I  believe  we  must  now  investigate  whether  it  also  has  several  motions, 
so  that  it  can  be  considered  one  of  the  planets.  That  it  is  not  the  center 
of  all  the  revolutions  is  proved  by  the  irregular  motions  of  the  planets, 
and  their  varying  distances  from  the  earth,  which  cannot  be  explained 
as  concentric  circles  with  the  earth  at  the  center.  Therefore,  since  there 
are  several  central  points,  no  one  will  without  cause  be  uncertain 
whether  the  center  of  the  universe  is  the  center  of  gravity  of  the  earth 
or  some  other  central  point.  I,  at  least,  am  of  the  opinion  that  gravity 
is  nothing  else  than  a  natural  force  planted  by  the  divine  providence  of 
the  Master  of  the  World  into  its  parts,  by  means  of  which  they,  assuming 
a  spherical  shape,  form  a  unity  and  a  whole.  And  it  is  to  be  assumed  that 
the  impulse  is  also  inherent  in  the  sun  and  the  moon  and  the  other 
planets,  and  that  by  the  operation  of  this  force  they  remain  in  the  spherical 
shape  in  which  they  appear;  while  they,  nevertheless,  complete  their 
revolutions  in  diverse  ways.  If  then  the  earth,  too,  possesses  other  motions 
besides  that  around  its  center,  then  they  must  be  of  such  a  character  as 
to  become  apparent  in  many  ways  and  in  appropriate  manners;  and 
among  such  possible  effects  we  recognize  the  yearly  revolution. 


Proof  that  the  Earth  Moves 


From  The  Sidereal  Messenger 

<L\.  ears  that  a  Dutchman  had  constructed  a  telescope,  by  the  aid  of 
which  visible  objects,  although  at  a  great  distance  from  the  eye  of  the 
observer,  were  seen  distinctly  as  if  near;  and  some  proofs  of  its  most 
wonderful  performances  were  reported,  which  some  gave  credence  to, 
but  others  contradicted.  A  few  days  after,  I  received  confirmation  of  the 
report  in  a  letter  written  from  Paris  by  a  noble  Frenchman,  Jaques 
Badovere,  which  finally  determined  me  to  give  myself  up  first  to  inquire 
into  the  principle  of  the  telescope,  and  then  to  consider  the  means  by 
which  I  might  compass  the  invention  of  a  similar  instrument,  which 
after  a  little  while  I  succeeded  in  doing,  through  deep  study  of  the  theory 
of  Refraction;  and  I  prepared  a  tube,  at  first  of  lead,  in  the  ends  of 
which  I  fitted  two  glass  lenses,  both  plane  on  one  side,  but  on  the  other 
side  one  spherically  convex,  and  the  other  concave.  Then  bringing  my 
eye  to  the  concave  lens  I  saw  objects  satisfactorily  large  and  near,  for 
they  appeared  one-third  of  the  distance  off.  and  nine  times  larger  than 
when  they  are  seen  with  the  natural  eye  alone.  I  shortly  afterwards  con- 
structed another  telescope  with  more  nicety,  which  magnified  objects 
more  than  sixty  times.  At  length,  by  sparing  neither  labour  nor  expense, 
I  succeeded  in  constructing  for  myself  an  instrument  so  superior  that 
objects  seen  through  it  appear  magnified  nearly  a  thousand  times,  and 
more  than  thirty  times  nearer  than  if  viewed  by  the  natural  powers  of 
sight  alone. 


It  would  be  altogether  a  waste  of  time  to  enumerate  the  number  and 
importance  of  the  benefits  which  this  instrument  may  be  expected  to 



confer,  when  used  by  land  or  sea.  But  without  paying  attention  to  its 
use  for  terrestrial  objects,  I  betook  myself  to  observations  of  the  heavenly 
bodies;  and  first  of  all,  I  viewed  the  Moon  as  near  as  if  it  was  scarcely 
two  semidiameters  of  the  Earth  distant.  After  the  Moon,  I  frequently 
observed  other  heavenly  bodies,  both  fixed  stars  and  planets,  with 
incredible  delight.  .  .  . 


There  remains  the  matter,  which  seems  to  me  to  deserve  to  be  con- 
sidered the  most  important  in  this  work,  namely,  that  I  should  disclose 
and  publish  to  the  world  the  occasion  of  discovering  and  observing  four 
planets,  never  seen  from  the  very  beginning  of  the  world  up  to  our  own 
times,  their  positions,  and  the  observations  made  during  the  last  two 
months  about  their  movements  and  their  changes*  of  magnitude.  .  .  . 

On  the  yth  day  of  January  in  the  present  year,  1610,  in  the  first  hour 
of  the  following  night,  when  I  was  viewing  the  constellations  of  the 
heavens  through  a  telescope,  the  planet  Jupiter  presented  itself  to  my 
view,  and  as  I  had  prepared  for  myself  a  very  excellent  instrument,  I 
noticed  a  circumstance  which  I  had  never  been  able  to  notice  before, 
owing  to  want  of  power  in  my  other  telescope,  namely,,  that  three  little 
stars,  small  but  very  bright,  were  near  the  planet;  and  although  I 
believed  them  to  belong  to  the  number  of  the  fixed  stars,  yet  they  made 
me  somewhat  wonder,  because  they  seemed  to  be  arranged  exactly  in  a 
straight  line,  parallel  to  the  ecliptic,  and  to  be  brighter  than  the  rest 
of  the  stars,  equal  to  them  in  magnitude.  The  position  of  them  with 
reference  to  one  another  and  to  Jupiter  was  as  follows: 

Ori.  *  *        O  *  Occ. 

On  the  east  side  there  were  two  stars,  and  a  single  one  towards  the  west. 
The  star  which  was  furthest  towards  the  east,  and  the  western  star, 
appeared  rather  larger  than  the  third. 

I  scarcely  troubled  at  all  about  the  distance  between  them  and  Jupiter, 
for,  as  I  have  already  said,  at  first  I  believed  them  to  be  fixed  stars;  but 
when  on  January  8th,  led  by  some  fatality,  I  turned  again  to  look  at 
the  same  part  of  the  heavens,  I  found  a  very  different  state  of  things, 
for  there  were  three  little  stars  all  west  of  Jupiter,  and  nearer  together 
than  on  the  previous  night,  and  they  were  separated  from  one  another 
by  equal  intervals,  as  the  accompanying  figure  shows. 


Ori.  O       *       *       *  Occ. 

At  this  point,  although  I  had  not  turned  my  thoughts  at  all  upon  the 
approximation  of  the  stars  to  one  another,  yet  my  surprise  began  to  be 
excited,  how  Jupiter  could  one  day  be  found  to  the  east  of  all  the  afore- 
said fixed  stars  when  the  day  before  it  had  been  west  of  two  of  them; 
and  forthwith  I  became  afraid  lest  the  planet  might  have  moved  differ- 
ently from  the  calculation  of  astronomers,  and  so  had  passed  those  stars 
by  its  own  proper  motion.  I,  therefore,  waited  for  the  next  night  with  the 
most  intense  longing,  but  I  was  disappointed  of  my  hope,  for  the  sky 
was  covered  with  clouds  in  every  direction. 

But  on  January  loth  the  stars  appeared  in  the  following  position  with 
regard  to  Jupiter,  the  third,  as  I  thought,  being 

Ori.  *        *        O  Occ. 

hidden  by  the  planet.  They  were  situated  just  as  before,  exactly  in  the 
same  straight  line  with  Jupiter,  and  along  the  Zodiac. 

When  I  had  seen  these  phenomena,  as  I  knew  that  corresponding 
changes  of  position  could  not  by  any  means  belong  to  Jupiter,  and  as, 
moreover,  I  perceived  that  the  stars  which  I  saw  had  always  been  the 
same,  for  there  were  no  others  either  in  front  or  behind,  within  a  great 
distance,  along  the  Zodiac — at  length,  changing  from  doubt  into  surprise, 
I  discovered  that  the  interchange  of  position  which  I  saw  belonged  not  to 
Jupiter,  but  to  the  stars  to  which  my  attention  had  been  drawn,  and  I 
thought  therefore  that  they  ought  to  be  observed  henceforward  with 
more  attention  and  precision. 

Accordingly,  on  January  nth  I  saw  an  arrangement  of  the  follow- 
ing kind: 

Ori.  *       *  O  Occ. 

namely,  only  two  stars  to  the  east  of  Jupiter,  the  nearer  of  which  was  dis- 
tant from  Jupiter  three  times  as  far  as  from  the  star  further  to  the  east; 
and  the  star  furthest  to  the  east  was  nearly  twice  as  large  as  the  other 
one;  whereas  on  the  previous  night  they  had  appeared  nearly  of  equal 
magnitude.  I,  therefore,  concluded,  and  decided  unhesitatingly,  that  there 
are  three  stars  in  the  heavens  moving  about  Jupiter,  as  Venus  and 
Mercury  round  the  Sun;  which  at  length  was  established  as  clear  as 
daylight  by  numerous  other  subsequent  observations.  These  observations 


also  established  that  there  are  not  only  three,  but  four,  erratic  sidereal 
bodies  performing  their  revolutions  round  Jupiter.  .  .  . 

These  are  my  observations  upon  the  four  Medicean  planets,  recently 
discovered  for  the  first  time  by  me;  and  although  it  is  not  yet  permitted 
me  to  deduce  by  calculation  from  these  observations  the  orbits  of  these 
bodies,  yet  I  may  be  allowed  to  make  some  statements,  based  upon  them, 
well  worthy  of  attention. 


And,  in  the  first  place,  since  they  are  sometimes  behind,  sometimes 
before  Jupiter,  at  like  distances,  and  withdraw  from  this  planet  towards 
the  east  and  towards  the  west  only  within  very  narrow  limits  of 
divergence,  and  since  they  accompany  this  planet  alike  when  its  motion 
is  retrograde  and  direct,  it  can  be  a  matter  of  doubt  to  no  one  that  they 
perform  their  revolutions  about  this  planet  while  at  the  same  time  they 
all  accomplish  together  orbits  of  twelve  years'  length  about  the  centre 
of  the  world.  Moreover,  they  revolve  in  unequal  circles,  which  is  evi- 
dently the  conclusion  to  be  drawn  from  the  fact  that  I  have  never  been 
permitted  to  see  two  satellites  in  conjunction  when  their  distance  from 
Jupiter  was  great,  ^whereas  near  Jupiter  two,  three,  and  sometimes  all 
four,  have  been  found  closely  packed  together.  Moreover,  it  may  be 
detected  that  the  revolutions  of  the  satellites  which  describe  the  smallest 
circles  round  Jupiter  are  the  most  rapid,  for  the  satellites  nearest  to 
Jupiter  are  often  to  be  seen  in  the  east,  when  the  day  before  they  have 
appeared  in  the  west,  and  contrariwise.  Also,  the  satellite  moving  in  the 
greatest  orbit  seems  to  me,  after  carefully  weighing  the  occasions  of  its 
returning  to  positions  previously  noticed,  to  have  a  periodic  time  of  half 
a  month.  Besides,  we  have  a  notable  and  splendid  argument  to  remove 
the  scruples  of  those  who  can  tolerate  the  revolution  of  the  planets 
round  the  Sun  in  the  Copernican  system,  yet  are  so  disturbed  by  the 
motion  of  one  Moon  about  the  Earth,  while  both  accomplish  an  orbit 
of  a  year's  length  about  the  Sun,  that  they  consider  that  this  theory  of 
the  universe  must  be  upset  as  impossible;  for  now  we  have  not  one 
planet  only  revolving  about  another,  while  both  traverse  a  vast  orbit 
about  the  Sun,  but  our  sense  of  sight  presents  to  us  four  satellites  circling 
about  Jupiter,  like  the  Moon  about  the  Earth,  while  the  whole  system 
travels  over  a  mighty  orbit  about  the  Sun  in  the  space  of  twelve  years. 


The  Orderly  Universe 


shining  objects  are  seen — the  sun  by  day,  the  moon  and  numerous 
stars  at  night.  In  comparison  with  the  enormous  earth  beneath  our  feet, 
they  all  appear  to  be  insignificant  bodies.  Indeed,  the  sun  and  the  moon 
are  often  hidden  from  our  view  by  a  passing  cloud,  while  the  stars  are 
only  scintillating  points  of  light.  Not  only  do  the  heavenly  bodies  appear 
to  be  relatively  small,  but  men  in  all  ages  almost  down  to  our  own  have 
believed  that  they  are  small.  The  general  conception  of  the  relative  impor- 
tance of  the  various  bodies  in  the  cosmos  is  illustrated  by  the  story  of 
creation  in  Genesis.  According  to  this  account,  after  the  earth  had  been 
created,  "God  made  two  great  lights"  in  the  sky  above,  "the  greater  light 
to  rule  the  day,  and  the  lesser  light  to  rule  the  night."  And  then,  almost 
as  if  it  were  an  afterthought,  "he  made  the  stars  also." 

Often  in  the  history  of  science  it  has  been  found  that  "things  are  not 
what  they  seem."  It  has  been  so  in  the  history  of  astronomy  to  a  marked 
degree.  Perhaps  in  no  other  field  of  exploration  have  the  differences 
between  appearances  and  realities  been  so  great.  On  the  one  hand,  this 
apparently  limitless  planet  on  which  we  dwell  has  been  reduced  relatively 
to  a  particle  of  dust  floating  in  the  immensity  of  space;  while,  on  the 
other  hand,  "the  greater  light,"  hanging  like  a  lamp  in  the  sky,  has  been 
expanded  to  a  flaming  mass  of  gas  a  million  times  greater  in  volume  than 
the  earth.  More  remarkable  still,  the  tiny  twinkling  stars,  instead  of  being 
fireflies  of  the  heavens,  are  in  reality  other  suns,  many  greater  than  our 
own,  whose  glories  are  dimmed  only  by  their  enormous  distances  from 
us;  and  the  soft  circle  of  light  which  we  know  as  the  Milky  Way  has 
been  found  to  be  a  vast  cosmic  system  of  twenty  thousand  million  stars. 

Amazing  are  the  differences  between  what  the  heavenly  bodies  appear 
to  be  and  what  they  actually  are.  Equally  amazing  are  the  differences 
between  the  intervals  of  time  within  the  range  of  direct  human  experience 



and  the  enormous  periods  covered  by  the  cosmic  processes.  Historians 
speak  of  the  civilizations  which  long  ago  flourished  in  the  valleys  of  the 
Nile  and  the  Euphrates  as  being  ancient,  and  from  the  standpoint  of 
human  history  they  are  ancient.  Yet  all  the  written  records  which  arche- 
ologists  have  recovered  from  the  buried  ruins  of  long-forgotten  cities 
date  back  less  than  ten  thousand  years,  which  is  only  a  moment  in  com- 
parison with  the  millions  of  years  of  the  geological  eras  or  with  the  three 
thousand  million  years  during  which  the  earth  has  existed  as  a  separate 
body.  Even  the  great  age  of  the  earth  is  only  a  small  fraction  of  the 
enormous  lifetime  of  a  star. 

Great  distances,  prodigious  masses,  and  long  intervals  of  time  are  not 
merely  interesting.  They  stir  our  imaginations,  exercise  our  reasoning 
powers,  expand  our  spirits,  and  change  our  perspective  with  respect  to 
all  the  experiences  of  life.  But  they  do  not  include  all  the  important  conse- 
quences of  astronomical  investigations.  Indeed,  they  do  not  directly 
include  that  which  is  most  important,  the  supreme  discovery  of  science — 
the  orderliness  of  the  universe. 

What  do  we  mean  by  "the  orderliness  of  the  universe"?  Astronomers 
found  from  painstaking  and  long-continued  observations  of  the  heavenly 
bodies  that  celestial  phenomena  recur  in  regular  sequences.  Though  the 
order  of  the  succession  of  events  in  the  heavens  is  often  somewhat  com- 
plex, it  is  nevertheless  systematic  and  invariable.  The  running  of  no  clock 
ever  approached  in  precision  the  motions  of  the  sun,  the  moon,  and  the 
stars.  In  fact,  to  this  day  clocks  are  corrected  and  regulated  by  comparing 
them  with  the  apparent  diurnal  motions  of  the  heavenly  bodies.  Since  not 
merely  a  few  but  hundreds  of  celestial  phenomena  were  long  ago  found 
to  be  perfectly  orderly,  it  was  gradually  perceived  that  majestic  order 
prevails  universally  in  those  regions  in  which,  before  the  birth  of  science, 
capricious  gods  and  goddesses  were  believed  to  hold  dominion.  .  .  . 


For  a  few  days  each  month  the  crescent  moon  may  be  seen  after  sunset 
in  the  western  sky.  In  a  week  it  changes  to  a  semicircle  of  light  directly 
south  on  the  meridian  at  the  same  hour;  in  another  week,  at  the  full 
phase,  it  rises  in  the  east  as  the  sun  sets.  If  observations  are  continued 
through  the  night,  the  full  moon  is  found  directly  south  at  midnight,  and 
setting  in  the  west  as  the  sun  rises.  Year  after  year  and  century  after 
century  this  shining  body  goes  through  its  cycles  of  changes,  each  cycle 
being  generally  similar  to  the  others  but  no  two  of  them  being  exactly 
alike.  It  is  not  surprising  that  primitive  peoples  should  have  regarded  it 
with  awe  and  determined  the  times  of  their  religious  ceremonies  by  its 


phases.  Indeed,  most  of  the  calendars  of  antiquity  were  based  upon  the 
phases  of  the  moon. 

Regularities  in  the  motions  of  the  moon  and  in  the  succession  of  its 
phases  have  always  been  found  by  those  who  have  carefully  followed 
celestial  phenomena.  But  these  approximations  to  cyclical  repetitions  are 
only  crude  hints  of  the  perfect  orderliness  which  accurate  and  long- 
continued  astronomical  observations  have  proved  to  exist.  Every  apparent 
departure  from  some  simple  theory  has  been  found  to  be  a  part  of  a 
greater  and  more  complicated  order.  The  observed  motion  of  the  moon 
is  compounded  out  of  more  than  a  thousand  cycles  whose  magnitudes 
and  phases  are  now  accurately  known.  The  theory  of  the  motion  of  the 
moon  is  so  perfect  that  its  position  can  be  computed  for  any  instant  in 
the  future,  even  for  a  thousand  years.  Indeed,  it  is  obvious  that  if  it  were 
not  possible  for  mathematicians  to  compute  accurately  the  motions  of  the 
moon,  they  could  not  unerringly  predict  all  the  circumstances  of  eclipses 
many  years  in  advance  of  their  occurrence. 

Astronomers  have  not  simply  worked  out  the  properties  of  the  motion 
of  the  moon  from  observations  of  its  positions  over  long  intervals  of  time. 
They  have  discovered  the  underlying  reason  for  all  the  complexities  of  its 
path  about  the  earth,  and  that  reason  is  that  it  moves  subject  to  the 
gravitational  attraction  of  the  earth  and,  to  a  lesser  degree,  of  the  more 
distant  sun.  This  force  which  prevents  the  moon  from  flying  away  from 
the  earth  is  sufficient  to  break  a  steel  cable  nearly  three 'hundred  miles 
in  diameter.  Yet  invisibly,  like  the  force  between  a  magnet  and  a  piece  of 
iron,  it  acts  across  the  240,000  miles  between  the  earth  and  the  moon. 
With  extraordinary  exactness  it  varies  inversely  as  the  square  of  the 
distance  between  these  bodies.  Together  with  the  attraction  of  the  sun 
on  the  earth  and  the  moon,  it  forms  an  infallible  basis  for  explaining  all 
the  peculiarities  of  the  motion  of  our  satellite.  Indeed,  in  numerous 
instances  it  has  enabled  mathematicians  to  anticipate  experience  and  to 
predict  phenomena  which  observations  later  confirmed. 

Mere  words  cannot  do  justice  to  the  marvelous  agreement  between 
theory  and  the  actual  motions  of  the  moon.  No  machine  ever  ran  with 
such  accuracy;  no  predictions  of  terrestrial  phenomena  were  ever  so  per- 
fectly fulfilled.  If  we  are  entitled  to  conclude  that  we  understand  any- 
thing whatever,  we  may  claim  that  we  understand  how  the  moon  moves 
around  the  earth  under  the  attractions  of  the  earth  and  the  sun.  .  .  . 

Evidently  the  moon  is  above  the  level  of  the  highest  clouds  and  far 
away  from  the  earth.  It  is  easy  to  understand  that  if  two  astronomers  are 
at  two  different  points,  they  will  see  the  moon  in  somewhat  different 
directions  from  their  points  of  observation:  and  it  is  almost  as  easy  to 


understand  that  from  the  distance  between  the  astronomers  and  the 
angle  at  which  the  moon  is  observed  its  altitude  above  the  earth  can 
be  computed.  From  such  observations  and  calculations,  astronomers  have 
found  that  the  distance  from  the  center  of  the  earth  to  the  center  of  the 
moon  varies  between  225,000  and  252,000  miles,  with  an  average  of  238,857 
miles.  This  distance  is  known  with  nearly  the  same  percentage  of  accuracy 
as  the  diameter  of  the  earth.  The  moon  moves  at  an  average  speed  of 
3,350  feet  per  second  in  an  orbit  so  large  that  in  going  this  distance  it 
deviates  from  a  straight  line  only  about  one  twentieth  of  an  inch. 

After  the  distance  to  the  moon  has  been  determined,  its  diameter  can 
be  computed  from  its  apparent  size.  This  shining  object  which  even  a 
small  button  held  at  arm's  length  will  hide  from  view  is  actually  2,160 
miles  in  diameter,  or  more  than  one  fourth  the  diameter  of  the  earth. 
Its  exterior  area  is  approximately  thirty  million  square  miles,  or  ten 
times  the  area  of  the  United  States.  Consequently,  there  is  abundant  room 
on  its  surface  for  mountains  and  valleys  and  plains  and  lakes  and  seas. 
There  are,  indeed,  many  mountains  on  the  moon's  surface,  both  isolated 
peaks  and  long  ranges,  and  there  are  valleys  and  plains,  but  no  lakes  or 
seas.  In  fact,  there  is  no  water  whatever  upon  its  surface,  nor  is  there  even 
an  atmosphere  surrounding  it. 

There  is  no  real  mystery  respecting  the  lack  of  air  and  water  on  the 
moon.  The  surface  gravity  of  this  small  world  (about  one  sixth  that  of 
the  earth)  is  not  sufficient  to  hold  the  swiftly  darting  molecules  of  an 
atmosphere  from  escaping  away  into  space.  Its  surface  is  a  desert,  unpro- 
tected by  clouds  or  an  atmosphere  from  the  burning  rays  of  the  sun 
during  its  day,  or  from  the  rapid  escape  of  heat  during  its  night.  Both 
extremes  of  its  surface  temperature  are  particularly  severe,  because  its 
period  of  rotation  is  about  29.5  times  that  of  the  earth.  For  nearly  fifteen 
of  our  days  a  point  on  its  surface  is  subjected  to  a  temperature  above  the 
boiling  point  of  water  on  the  earth;  for  an  equal  interval  of  time  it  freezes 
in  a  temperature  which  descends  far  toward  the  absolute  zero  (about 
—460°  Fahrenheit),  Evidently  it  cannot  be  the  abode  of  life.  . . . 


From  a  certain  point  of  view  the  earth  is  for  us  a  very  important  body, 
more  important  than  every  celestial  body  except  the  sun.  It  has  been  the 
home  of  the  life  stream  of  which  we  are  a  part  for  more  than  a  thousand 
million  years.  It  will  be  the  home  of  our  successors  until  our  race  becomes 
extinct.  Our  very  existence  depends  upon  it. 

From  another  point  of  view,  which  we  shall  now  take,  the  earth  is  not 
very  important.  It  is  only  one  of  nine  known  planets  which  revolve 


around  the  sun,  each  of  them  held  in  its  orbit  by  the  attraction  of  the 
great  central  mass.  Thus,  the  very  brilliant  silvery  object  which  we  see 
in  the  western  evening  sky  (and  eastern  morning  sky)  every  nineteen 
months  is  the  planet  Venus,  a  world  in  size  and  in  most  other  respects 
similar  to  our  earth.  The  wandering  conspicuous  red  body  which  appears 
in  the  evening  sky  every  twenty-six  months  is  the  planet  Mars,  and  the 
brighter  yellowish  object  which  returns  every  thirteen  months  is  Jupiter. 
These  bodies  and  two  others,  Mercury  and  Saturn,  were  called  planets 
(or  wanderers)  by  the  ancients  because  they  are  constantly  moving  with 
respect  to  the  stars.  .  .  . 

It  was  not  until  the  first  decades  of  the  seventeenth  century  that  Kepler 
worked  out  from  the  observations  of  Tycho  Brahe  the  properties  of  the 
planetary  orbits;  it  was  not  until  the  latter  part  of  the  same  century  that 
Newton  proved  the  law  of  gravitation  and  explained  by  means  of  it  the 
motions  of  the  planets  and  of  the  moon,  the  oblateness  of  the  earth,  and 
the  ebb  and  flow  of  the  tides.  These  great  achievements  mark  the  closing 
of  an  epoch  in  the  history  of  the  thought  of  the  world  and  the  beginning 
of  a  new,  for  they  entirely  overthrew  earlier  views  respecting  the  nature 
of  the  cosmos  and  established  others  which  were  entirely  different.  They 
permanently  removed  man  from  his  proud  position  at  the  center  of  crea- 
tion and  placed  him  on  a  relatively  insignificant  body;  but,  as  a  compen- 
sation, they  rescued  him  from  a  universe  of  chance  and  superstition  and 
gave  him  one  of  unfailing  and  majestic  orderliness. 

There  have  been  many  impressive  illustrations  of  the  orderliness  of 
the  universe  and  of  our  understanding  of  that  order,  but  none  has  been 
more  dramatic  than  the  discovery  of  Neptune.  This  remarkable  story 
opened  in  1781  with  the  discovery  of  the  planet  Uranus  (the  first  one 
discovered  in  historic  times)  by  William  Herschel;  it  closed  with  the 
discovery  of  Neptune  in  1846. 

After  Uranus  had  been  observed  for  a  few  months,  mathematicians 
computed  its  orbit  and  directed  observers  where  to  point  their  telescopes 
in  order  to  see  this  planet,  for  it  is  too  faint  to  be  observable  with  the 
unaided  eye.  For  nearly  forty  years  Uranus  was  always  found  precisely 
where  the  mathematicians  said  it  would  be  seen.  Then  there  began  to  be 
an  appreciable  difference  between  theory  and  the  observations.  By  1830 
the  discrepancies  had  become  serious;  by  1840  they  were  intolerably  large. 
Although  the  discrepancies  were  intolerably  large  to  scientists  they  would 
have  been  negligible  to  anyone  else  in  the  world.  During  the  sixty  years 
following  the  discovery  of  Uranus  it  did  not  depart  from  its  predicted 
positions  by  an  amount  large  enough  to  be  observable  without  the  aid 
of  a  telescope.  Since  mankind  had  never  even  known  of  the  existence 


of  Uranus  until  1781,  it  at  first  seems  absurd  that  scientists  should  have 
been  disturbed  by  very  minute  unexplained  peculiarities  in  its  motions — 
variations  from  theory  so  slight  that  they  were  not  observable  until  the 
lapse  of  about  forty  years.  The  theories,  however,  were  believed  to  be 
very  perfect.  Hence  the  discrepancies  called  into  question  their  exactness, 
or  perhaps  even  the  soundness  of  mathematical  reasoning.  In  fact,  the 
unexplained  difference  between  theory  and  observation  threw  a  doubt 
on  our  ability  to  discover  and  to  apply  the  laws  of  nature.  For  this  reason 
the  motion  of  Uranus  became  one  of  the  most  important  problems  in 

In  1846  order  was  restored  by  a  brilliant  discovery.  Some  years  earlier 
it  had  been  suggested  that  Uranus  was  departing  slightly  from  its  pre- 
dicted orbit  as  the  consequence  of  the  attraction  of  an  unknown  world.  The 
problem  was  to  find  the  unknown  body  from  its  minute  effects  on  Uranus. 
No  brief  statement  can  give  any  adequate  realization  of  the  difficulties 
of  the  problem.  The  leading  mathematicians  of  the  time  thought  it  could 
not  be  solved.  But  two  young  men,  J.  C.  Adams,  of  England,  and  U.  J. 
Leverrier,  of  France,  inspired  with  the  optimism  and  energy  of  youth, 
calculated  where  the  unknown  world  would  be  found.  Their  predictions 
were  brilliantly  fulfilled  by  the  discovery  of  Neptune  on  February  23, 
1846,  by  J.  G.  Galle,  a  young  German  astronomer.  With  this  discovery, 
the  motion  of  Uranus  again  was  fully  explained,  the  laws  of  nature  and 
our  reasoning  powers  were  no  longer  in  question,  and  the  universe  was 
once  more  orderly.  .  .  . 

No  experiences  give  us  a  better  understanding  of  distances  than  those 
obtained  from  long  journeys.  Consequently,  let  us  in  imagination  board 
some  miraculous  skyship,  of  which  everyone  has  often  dreamed,  and 
travel  from  the  sun  to  the  various  planets. 

Obviously  our  skyship  must  fly  rapidly  or  we  shall  not  live  long  enough 
to  cross  the  great  distance  from  one  planet  to  another.  On  the  other  hand, 
if  it  travels  at  too  great  speed  we  shall  not  be  able  to  descend  safely  upon 
the  surface  of  a  planet.  So  let  us  suppose  our  skyship  can  traverse  the 
interplanetary  spaces  at  the  rate  of  a  thousand  miles  per  hour,  a  speed  of 
travel  at  which  one  might  eat  breakfast  in  the  eastern  part  of  the  United 
States  and  luncheon  in  Europe.  Let  us  start  from  the  surface  of  the  sun. 
Perhaps  before  directing  our  way  toward  Mercury  we  should  circle  around 
this  great  center  of  attraction.  Jauntily  we  set  out  and  travel  continuously, 
but  we  do  not  complete  the  circuit  of  the  sun  and  get  back  to  our  point 
of  departure  until  113  days,  or  nearly  four  months,  have  elapsed. 

With  some  trepidation  at  leaving  the  sun  and  plunging  into  the  inter- 
planetary spaces,  we  depart  for  Mercury,  which  we  reach  in  four  years  and 


one  month.  In  three  and  one  half  years  we  are  at  the  distance  of  Venus; 
in  three  more  at  the  orbit  of  the  earth,  ten  years  and  seven  months  after 
we  left  the  sun.  Since  five  years  and  seven  months  more  are  required  to 
reach  Mars  from  the  orbit  of  the  earth,  it  takes  our  skyship  sixteen  years 
and  two  months  to  fly  from  the  sun  to  this  planet.  Obviously  the  intervals 
of  time  required  for  these  sky  voyages  are  so  great  that  they  fail  to  give  us 
any  real  understanding  of  the  enormous  distances  we  traverse.  Yet  let  us 
continue*  on  our  way. 

We  arrive  at  Jupiter  in  fifty-five  years  after  we  left  the  sun;  at  Saturn  in 
lor  years;  at  Uranus  in  203  years;  and  at  Neptune  in  318  years.  If  we 
should  continue  to  distant  and  inconspicuous  Pluto,  we  should  arrive  there 
in  420  years.  And  yet  at  the  rate  of  our  travel  we  could  eat  breakfast  in 
New  York,  luncheon  in  London,  and  return  to  New  York  for  dinner  anc 
the  theater.  .  .  . 


Since  the*  dawn  of  history  and,  indeed,  for  millions  of  years  before  the 
origin  of  man,  the  sun  and  the  moon  have  not  changed  appreciably  in 
appearance.  But  there  are  celestial  visitors,  the  comets,  which  do  not 
possess  these  qualities  of  permanence  and  uniformity  from  which  the 
orderliness  of  the  universe  was  first  perceived.  These  objects  often  come 
quite  unexpectedly  out  of  the  depths  of  space  for  a  brief  visit  to  the  inte- 
rior of  the  solar  system,  and  then  they  recede  back  into  the  night  from 
which  they  came.  They  are  not  of  fixed  shape  or  constant  dimensions  like 
the  planets.  The  typical  comet  consists  of  a  small  nucleus,  generally  star- 
like  in  appearance,  surrounded  by  a  vast  gaseous  envelope  which  varies 
enormously  in  volume,  sometimes  being  as  large  as  the  sun;  while  from  its 
head  there  streams  out  a  tail,  perhaps  fifty  millions  of  miles  in  length, 
which  in  exceptional  cases  appears  to  reach  a  third  of  the  way  across  the 

It  is  not  strange  that  primitive  peoples  and,  indeed,  all  men  until  only 
two  or  three  centuries  ago  regarded  comets  with  superstitious  fear.  Our 
predecessors  believed  that  these  bizarre-appearing  objects  are  malignant 
spirits  prowling  through  our  atmosphere,  or  at  least  that  they  are  portents 
of  wars  and  pestilences.  After  centuries  of  belief  in  these  superstitions, 
accepted  alike  by  the  ignorant  and  the  learned,  by  theologians  and 
scientists,  observations  led  finally  to  the  truth. 

Tycho  Brahe  (1571-1630),  the  greatest  and  last  observer  before  the  inven^ 
tion  of  the  telescope,  comparing  the  different  apparent  directions  of  the 
comet  of  1577  as  seen  simultaneously  from  various  places  in  Europe, 
proved  that  this  terrifying  object  was  far  beyond  our  atmosphere  and  at 


least  as  distant  as  the  moon.  By  this  demonstration  he  removed  comets 
from  the  apparent  vagaries  of  atmospheric  phenomena  to  the  orderly 
domains  of  the  celestial  bodies. 

It  should  not  be  thought  that  comets  and  thqjr  motions  were  at  once 
completely  understood.  The  phenomena  they  present  are  far  too  com- 
plicated for  an  easy  explanation.  In  fact,  the  determination  of  the  proper- 
ties of  their  paths  through  the  solar  system  had  to  await  Newton's  dis- 
covery of  the  law  of  gravitation  in  1686  and  his  use  of  it  in  explaining  the 
celestial  motions.  He  devised  methods  of  determining  the  orbits  of  comets, 
however  elongated  they  might  be. 

A  lifelong  friend  of  Newton,  Edmund  Halley,  applied  Newton's 
methods  to  computing  the  orbit  of  a  great  comet  which  had  been  observed 
in  1682.  After  an  enormous  amount  of  work  on  this  and  earlier  comets, 
he  proved  that  it  revolves  in  a  very  elongated  path,  returning  to  the  neigh- 
borhood of  the  sun  about  every  seventy-five  years.  He  concluded  that  it 
was  identical  with  comets  which  had  been  observed  in  1456,  1301,  1145* 
1066,  and  at  various  other  times;  he  boldly  predicted  it  would  return 
in  1759,  and  it  did.  It  came  again  according  to  predictions  in  1835,  and 
most  recently  in  1910.  Now  it  is  far  out  in  its  long  orbit.  It  has  been 
invisible  for  twenty-five  years  and  will  not  be  seen  again  for  forty  years 
in  the  future.  Yet  mathematicians  can  follow  it  with  perfect  certainty, 
and  long  before  its  next  return  they  will  compute  the  very  day  when  it 
will  arrive  at  the  point  of  its  orbit  nearest  the  sun. 

.  .  .  Comets  differ  enormously  from  one  another  in  brightness,  volume, 
length  of  tails,  and  internal  activity.  From  three  to  eleven  comets  are 
observed  each  year,  nearly  all  of  them  being  so  faint  as  to  be  invisible 
without  optical  aid.  Occasionally  one  appears  which  is  bright  enough  to- 
be  easily  visible  to  the  unaided  eye;  about  three  or  four  times  a  century 
a  very  great  one  becomes  the  most  conspicuous  object  in  the  night  sky. 
The  tails  of  comets  develop  and  increase  in  length  as  these  objects 
approach  the  sun  and  diminish  and  disappear  as  they  recede  again* 
While  a  comet  is  approaching  the  sun,  its  tail  streams  out  behind;  as. 
it  recedes,  its  tail  projects  out  ahead  of  it.  ... 


In  comparison  with  the  universe  in  general,  only  one  object  in  the 
solar  system  is  worth  mentioning,  and  that  object  is  the  sun.  It  is  a 
million  times  greater  than  the  earth  in  volume  and  a  thousand  times 
greater  in  mass  than  all  the  planets  combined.  It  holds  the  little  planets 
under  its  gravitative  control,  it  lights  and  warms  them  with  its  abun- 
dant rays,  it  takes  them  with  it  in  its  enormous  excursions  among  the  stars. 


How  brilliant  the  light  of  the  noonday  sun  is!  In  comparison  with  it 
all  artificial  lights  are  feeble  and  dull.  How  intensely  it  warms  the  sur- 
face of  the  earth  on  a  summer's  day!  This  general  impression  is  not 
erroneous,  for  accurate  jneasurements  prove  that  when  its  rays  fall  per- 
pendicularly upon  the  surface  of  the  earth  radiant  energy  is  received 
from  it  at  the  rate  of  1.5  horsepower  per  square  yard.  Under  the  same 
condition  of  perpendicular  rays,  a  square  mile  of  surface  receives  radiant 
energy  from  the  sun  at  the  rate  of  4,646,400  horsepower,  or  at  the  rate  of 
330  million  million  (330,000,000,000,000)  horsepower  on  the  whole  earth. 
If  this  energy  were  divided  equally  among  the  two  billion  human  beings 
now  living  on  the  earth,  each  of  them  would  have  more  than  a  hundred 
thousand  horsepower  for  his  use. 

As  enormous  as  is  the  energy  received  by  the  earth  from  the  sun,  it  is 
trivial  compared  with  the  amount  radiated  by  the  sun,  for  the  earth  as 
seen  from  the  sun  would  appear  to  be  only  a  point,  somewhat  smaller 
than  Venus  appears  to  us  when  it  is  the  bright  evening  star.  It  is  evident 
that  such  a  distant  and  apparently  insignificant  object  would  intercept  only 
a  very  small  fraction  of  the  solar  energy  streaming  out  from  it  in  every 
direction.  It  is  found  by  computation  that  the  earth  intercepts  only  one 
two-billionth  of  the  energy  radiated  by  the  sun.  Otherwise  expressed,  the 
sun  radiates  more  energy  in  a  second  than  the  earth  receives  in  sixty  years. 

Obviously  the  sun  must  be  very  hot,  for  otherwise  it  would  not  radiate 
energy  at  an  enormous  rate.  By  several  methods  it  is  found  that  the  tem- 
perature of  its  exterior  radiating  layers  is  about  ten  thousand  degrees 
Fahrenheit,  or  far  beyond  the  temperature  required  for  melting  and 
volatilizing  iron  and  other  similar  substances.  In  its  deep  interior  the 
temperatures  are  enormously  higher,  mounting  to  at  least  several  million 

The  temperature  of  the  sun's  interior  has  not,  of  course,  been  measured 
by  any  direct  means,  for  the  depths  of  the  sun  are  quite  inaccessible  to  us. 
But  science  often  penetrates  inaccessible  regions  by  reasoning,  as  it  does 
in  this  case.  The  general  principles  underlying  the  method  used  in  this 
problem  are  as  follows:  Each  layer  of  the  sun  weighs  down  upon  the  one 
directly  beneath  it  and  tends  to  compress  it.  This  tendency  to  compression 
of  a  layer  is  balanced  by  the  expansive  forces  due  to  its  temperature.  Now 
the  rates  of  increase  downward  in  both  density  and  temperature  can  be 
determined  by  the  condition  that  the  entire  mass  of  the  sun  shall  be  in 
equilibrium.  The  results  are  subject  to  some  uncertainties,  however,  because 
of  our  lack  of  knowledge  of  the  properties  of  matter  under  the  extreme 
conditions  of  pressure  and  temperature  prevailing  deep  in  the  sun. 

When  we  recall  the  terrestrial  storms  that  are  produced  by  unequal 


heating  of  different  portions  of  the  earth's  atmosphere,  we  naturally  ex- 
pect extremely  violent  disturbances  on  the  sun.  The  wildest  flights  of  our 
imagination,  however,  never  approach  the  realities,  for  often  masses  of 
enormously  heated  gases  a  hundred  times  greater  than  the  earth  in  volume 
shoot  upward  from  its  surface,  sometimes  farther  than  from  the  earth 
to  the  moon.  Particularly  in  intermediate  latitudes  on  each  side  of  the  solar 
equator  there  are  storm  zones  in  which  great  whirling  sun  spots  appear. 
These  sun-spot  disturbances,  ranging  from  a  few  thousand  up  to  more 
than  a  hundred  thousand  miles  in  diameter,  have  centers  which  appear 
dark  in  contrast  to  the  surrounding  bright  surface,  though  they  are  more 
luminous  than  the  filament  of  an  electric  light.  In  them  incandescent  gases 
surge  and  billow,  and  from  their  borders  eruptions  to  great  altitudes  are 
particularly  abundant.  If  our  earth  were  placed  on  the  surface  of  the  sun 
it  would  be  tossed  about  like  a  pebble  in  a  whirlpool;  it  would  be  melted 
and  dissipated  like  a  snowflake  in  a  seething  lake  of  lava.  .  .  . 

If  the  sun  were  dissipating  its  mass  into  space,  scientists  would  natu- 
rally inquire  how  it  is  restored,  but  until  about  1850  they  did  not  ask 
the  same  question  respecting  the  energy  it  radiates.  Until  that  time  they 
did  not  realize  that  energy  is  something  quantitative  and  measurable,  and 
hence  that  its  origin  requires  explanation.  The  sun  cannot  be  a  body  which 
was  once  much  hotter  than  at  present  and  which  is  slowly  cooling  off, 
for  if  this  were  all  there  is  to  its  heat  it  would  not  have  lasted  a  thou- 
sandth of  the  long  periods  of  the  geological  ages.  It  cannot  be  simply 
burning,  for  the  heat  produced  by  its  combustion,  even  if  it  were  composed 
of  pure  coal  and  oxygen,  would  last  only  a  few  thousand  years.  If  it 
were  contracting,  the  heat  generated  in  the  process  would  maintain  its 
radiation  only  a  few  million  years,  which  is  less  than  one  per  cent  of  the 
interval  during  which  it  has  shed  its  warm  rays  upon  the  earth  at  approxi- 
mately the  present  rate. 

Recently  very  conclusive  reasons  have  been  found  for  believing  that  the 
energy  the  sun  radiates  is  due  to  transformations  of  its  elements,  partic- 
ularly of  hydrogen,  into  heavier  elements,  and  probably  to  the  transforma- 
tion of  matter  into  energy  in  accordance  with  Einstein's  principle  of  the 
fundamental  equivalence  of  mass  and  energy.  These  sources  of  energy  are 
of  an  entirely  different  and  higher  order  of  magnitude  than  any  hereto- 
fore considered  by  scientists.  Although  the  mass  equivalent  of  the  energy 
radiated  by  the  sun  in  a  second  is  over  4,000,000  tons,  the  mass  of  the  sun 
is  so  enormous  that  it  will  not  be  reduced  through  radiation  by  so  much 
as  one  per  cent  in  150,000,000,000  years.  Consequently,  it  is  not  surprising 
that  the  geological  evidence  is  conclusive  that  the  earth  has  received  solar 
energy  at  substantially  the  present  rate  for  perhaps  a  thousand  million 


years.  Even  this  long  interval  of  time  is  only  a  very  small  fraction  of  the 
period  during  which  the  earth  will  continue  in  the  future  to  be  lighted 
and  warmed  by  the  sun  almost  precisely  as  it  is  at  present.  The  fears  once 
held  that  in  a  few  million  years  the  light  of  the  sun  will  fail  have  proved 
groundless,  and  scientists  no  longer  look  forward  to  a  time  when  the  earth, 
cold  and  lifeless,  will  circulate  endlessly  around  a  dark  center  of  attraction. 

One  of  the  miracles  of  science  has  been  the  determination  of  the  composi- 
tion of  the  sun. . . .  The  normal  ear  has  the  ability  to  distinguish  separately 
a  mixture  of  a  considerable  number  of  tones.  The  eye  has  no  correspond- 
ing power — a  mixture  of  blue  and  yellow,  for  example,  appears  as  a 
single  color  (green)  and  not  as  a  combination  of  two  colors.  Fortunately, 
a  very  remarkable  instrument,  the  spectroscope,  separates  a  mixture  of  light 
into  its  component  colors,  or  wave  lengths,  and  enables  the  astronomer 
to  determine  precisely  what  wave  lengths  are  present  in  the  radiation 
from  the  sun,  or,  indeed,  from  any  other  celestial  body  from  which 
sufficient  radiant  energy  is  received.  .  .  . 

Of  the  ninety  elements  known  on  the  earth,  at  least  fifty  have  been  found 
to  exist  in  the  atmosphere  of  the  sun  in  the  gaseous  state,  and  the  presence 
of  several  others  is  probable.  The  elements  found  in  considerable  abun- 
dance in  the  sun  include  hydrogen,  helium,  oxygen,  magnesium,  iron, 
silicon,  sodium,  potassium,  calcium,  aluminum,  nickel,  manganese, 
chromium,  cobalt,  titanium,  copper,  vanadium,  and  zinc.  Some  of  the 
heaviest  elements,  such  as  gold  and  uranium,  have  not  been  found  in  the 
sun's  atmosphere,  perhaps  because  they  lie  at  low  levels.  .  .  . 


As  the  sun  rises,  all  the  sparkling  stars  which  sprinkle  the  clear  night 
sky  pale  into  insignificance  and  totally  disappear.  Yet  actually  they  are  suns, 
most  of  those  which  are  visible  to  the  unaided  eye  being  much  greater 
than  our  own.  Indeed,  some  of  them  radiate  thousands  of  times  as  much 
light,  and  a  few  are  known  which  are  millions  of  times  greater  in  volume. 
Their  apparent  insignificance  is  due  to  their  incomprehensibly  enormous 

In  order  to  bring  within  the  range  of  our  understanding  the  distance 
from  the  sun  to  the  earth,  we  computed  the  time  necessary  for  an 
imaginary  skyship  to  travel  from  one  of  these  bodies  to  the  other  at  the  rate 
of  a  thousand  miles  per  hour.  We  found  that  if  it  continued  on  its  way 
night  and  day,  without  pausing,  it  would  require  ten  years  and  seven 
months  to  traverse  the  ninety-three  million  miles  between  the  center  of 
our  system  and  this  little  planet  of  ours.  Even  with  the  aid  of  this  calcula- 
tion we  do  not  grasp  the  significance  of  the  distances  in  the  solar  system. 


Perhaps  we  shall  improve  our  understanding  of  the  distances  in  the 
solar  system  by  noting  that  the  velocity  we  assumed  for  our  skyship  was 
more  than  30  per  cent  greater  than  that  of  sound  in  our  atmosphere,  for 
sounds  travels  at  the  rate  of  only  736  miles  per  hour.  Let  us  assume  that 
sound  could  come  from  the  sun  to  us  at  this  speed.  Then,  if  we  should 
see  some  tremendous  solar  explosion  and  should  expectantly  await  its 
thunders,  we  should  be  held  in  suspense  before  hearing  *it  for  more  than 
fourteen  years. 

If  we  fail  to  comprehend  the  great  distances  between  the  members  of 
our  solar  system,  we  naturally  shall  fall  far  short  of  grasping  as  realities 
the  enormously  greater  distances  to  the  stars.  Yet  we  must  attempt  to  do 
so,  and  we  shall  find  that  our  understanding  of  these  distances  increases  as 
we  struggle  with  them.  Let  us  start  with  the  nearest  star  visible  without 
optical  aid  from  northern  latitudes,  the  brilliant  Sirius,  the  brightest 
star  in  all  the  sky.  This  beautiful  bluish-white  object  is  on  the  southern 
meridian  at  eight  o'clock  in  the  evening  about  the  first  of  March  each 
year.  Astronomers  have  found  by  measurements  that  its  distance  is  51,700,- 
000,000,000  miles,  or  more  than  550,000  times  the  distance  from  the  sun  to 
the  earth.  Therefore,  more  than  6,000,000  years  would  be  required  for 
our  imaginary  skyship  to  fly  from  the  solar  system  to  Sirius. 

In  view  of  the  enormous  distances  to  even  the  nearest  of  the  stars,  we 
naturally  wonder  how  astronomers  have  measured  them  and  whether, 
after  all,  they  are  not  merely  conjectures  resting  upon  no  substantial 
foundation.  The  method  of  determining  the  distances  of  the  relatively 
near  stars  is  essentially  the  same  as  that  used  in  determining  the  distance 
to  the  moon,  namely,  measuring  the  differences  in  their  directions  as  seen 
from  two  different  points.  At  some  convenient  time  in  the  year  the  star 
Sirius,  for  example,  is  observed  to  be  in  a  certain  direction  from  the 
earth.  A  few  months  later,  after  the  earth  has  moved  many  millions  of 
miles  in  its  orbit,  Sirius  is  found  to  be  in  a  slightly  different  direction. 
From  this  change  in  direction  and  the  distance  apart  of  the  two  points 
of  observation  the  distance  of  Sirius  is  readily  computed.  Obviously,  the 
method  is  entirely  sound,  and  in  the  case  of  a  star  no  more  distant  than 
Sirius  it  is  known  that  the  results  are  not  uncertain  to  more  than  about 
one  per  cent  of  their  value. 

Although  the  direct  method  of  measuring  stellar  distances  is  relatively 
simple,  the  difficulties  of  putting  it  into  effect  are  in  general  enormous  be- 
cause of  the  remoteness  of  the  stars.  Indeed,  the  greatest  observed  differ- 
ence in  direction  of  Sirius  as  observed  from  the  earth  from  two  points  in 
its  orbit  separated  by  as  great  a  distance  as  even  that  from  the  earth  to  the 
sun  is  extremely  small.  It  is  as  small  as  the  difference  in  direction  of  an 


object  twenty-two  miles  away  wher  viewed  first  with  one  eye  and  then 
with  the  other.  Moreover,  only  four  or  five  other  known  stars,  all  of  which 
except  one  are  so  faint  as  to  be  invisible  without  optical  aid,  are  as  near  to 
us  as  Sirius.  Indeed,  all  except  a  few  hundred  stars  out  of  the  millions 
which  can  be  photographed  through  large  telescopes  are  so  very  remote 
that  their  distances  cannot  be  measured  by  the  direct  method  which  has 
been  outlined.  Nevertheless,  our  knowledge  of  the  distances  of  the  stars 
does  not  stop  with  this  limited  number,  for  astronomers  with  extraor- 
dinary skill  have  used  their  knowledge  of  the  distances  and  other  prop- 
erties of  these  nearer  stars  as  a  basis  for  several  other  methods  which 
reach  enormously  farther  into  space. 

Before  taking  up  the  characteristics  of  the  stars  we  shall  define  a  more 
convenient  unit  for  stellar  distances  which  we  shall  often  have  occasion  to 
use.  It  is  the  distance  light  travels  in  interstellar  space  in  a  year,  known  as 
the  light-year.  Since  light  travels  in  a  vacuum  at  the  rate  of  about  186,000 
miles  per  second,  the  light-year  is  5,880,000,000,000  miles,  or  about  60,000 
times  the  distance  from  the  sun  to  the  earth.  The  star  Sirius  is  distant  8.8 
light-years;  the  stars  of  the  Big  Dipper  are  distant  70  to  80  light-years; 
the  Pleiades,  about  200  light-years;  the  brighter  stars  in  Orion,  about  500 
light-years;  and  the  star  clouds  which  make  up  the  Milky  Way  thousands 
of  light-years. 

In  spite  of  the  enormous  distances  of  the  stars  a  great  deal  has  been 
learned  about  them  as  individual  bodies.  In  the  first  place,  they  consist 
of  a  number  of  classes  depending  upon  the  properties  of  the  light  they 
radiate  as  determined  by  the  spectroscope.  At  one  extreme  are  the  blue 
Class  B  stars,  of  which  a  number  of  the  brighter  stars  in  Orion  are  exam- 
ples. These  stars,  which  radiate  many  thousand  times  as  much  light  as 
our  sun,  are  enormous  bodies  whose  exterior  atmospheres  are  at  tem- 
peratures ranging  from  80,000  to  100,000  degrees  Fahrenheit.  In  their 
atmospheres  are  spectral  evidences  of  only  hydrogen,  helium,  oxygen,  and 

Next  come  the  Class  A  stars,  which  are  not  quite  so  hot  or  brilliant  as 
the  Class  B  stars.  Sirius  is  a  splendid  example  of  this  class.  Its  surface 
temperature  is  nearly  twice  that  of  the  sun,  and  it  radiates  twenty-seven 
times  as  much  light.  Then  follow  the  Class  F  stars,  of  which  Canopus  and 
Procyon  are  illustrations.  These  stars  approach  in  temperature,  brilliance, 
and  composition  the  Class  G  stars  to  which  Capella  and  the  sun  belong. 
Nearly  half  of  all  the  stars  in  the  catalogues  of  stellar  spectra  are  closely 
related  to  the  sun.  Only  a  few  are  giants  of  Class  A,  and  a  still  smaller 
number  are  supergiants  of  Class  B. 

Beyond  the  stars  in  the  spectral  sequence  of  class  G,  to  which  the  *un 


belongs,  come  the  cooler  and  ruddier  stars  of  Class  K,  of  which  Arcturus 
and  Aldebaran  are  notable  examples.  So  far  the  stars  of  each  spectral 
class  connect  by  insensible  gradations  with  those  of  the  next  class.  But  at 
the  stars  of  Class  K  there  is  a  discontinuity.  The  next  class  in  the  order 
in  which  they  are  usually  given  are  those  of  Class  M,  of  which  Betelgeuse 
and  Antares  are  examples.  The  atmospheres  of  these  stars  are  at  relatively 
low  temperatures,  as  would  naturally  be  inferred  from  their  colors,  and 
they  contain  many  compounds  as  well  as  individual  chemical  elements. 
There  are  three  other  classes  of  stars,  classes  N,  R,  and  S,  which  have  no 
well-defined  relationship  to  the  other  classes.  They  are  all  faint,  with  one 
or  two  exceptions  being  far  beyond  the  range  of  the  unaided  eye,  they 
are  very  few  in  number,  and  they  are  deep  red  in  color.  , . . 

In  1650,  forty  years  after  the  invention  of  the  telescope  by  Galileo,  the 
star  at  the  bend  of  the  handle  of  the  Big  Dipper,  which  theretofore  looked 
like  an  ordinary  star,  was  found  to  consist  of  two  stars  apparently  almost 
touching  each  other.  It  is  now  known,  however,  that  these  two  stars  are 
hundreds  of  times  as  far  apart  as  are  the  earth  and  the  sun.  The  discovery 
of  this  pair  has  been  followed  by  the  discovery  of  nearly  20,000  other 
double  stars.  Probably  a  few  of  these  double  pairs  consist  of  two  unrelated 
stars  which  happen  to  be  for  a  time  almost  in  the  same  direction  from 
us,  but  in  nearly  all  cases  they  are  actually  twin  suns  revolving  around 
their  center  of  gravity.  The  periods  of  revolution  of  most  of  them  are  so 
long,  however,  that  they  have  not  been  determined  from  observations  in 
the  relatively  short  intervals  since  their  discovery.  .  .  . 

In  certain  cases  the  plane  of  revolution  of  a  double  star  passes  through  or 
near  the  present  position  of  the  solar  system.  It  is  clear  that  when  the  two 
stars  of  such  a  pair  are  in  a  line  with  the  earth,  one  wholly  or  partially 
eclipses  the  other,  and  at  such  times  the  light  received  from  the  pair  is 
temporarily  reduced.  If  the  two  stars  are  equal  in  volume  and  equally 
bright,  the  light  received  by  the  earth  at  the  time  of  eclipse  is  one  half 
its  normal  value.  If  one  star  is  totally  dark,  it  may  entirely  eclipse  the 
luminous  star.  It  is  evident  that  many  cases  are  theoretically  possible,  and 
it  is  an  interesting  fact  that  nearly  all  of  them  have  been  observed. 

It  is  clearly  not  difficult  to  determine  the  periods  of  revolution  of  these 
variable  stars,  as  they  are  called,  for  their  periods  are  defined  by  the  inter- 
vals between  their  eclipses.  But  to  determine  the  distance  between  the 
components  of  such  a  pair  is  quite  another  matter,  for  they  are  so  close 
together  that  they  appear  to  be  a  single  star.  Fortunately,  a  remarkable 
application  of  the  spectroscope,  which  cannot  be  explained  here,  enables 
the  astronomer  to  measure  the  relative  velocity  of  a  pair  in  their  orbit; 


and  from  this  velocity  and  the  period  of  revolution  of  a  pair  he  computes 
the  perimeter  of  their  orbit,  and  then  their  distance  apart.  .  .  . 

Many  stars,  however,  are  variables  as  a  consequence  of  change  in  the 
rates  of  their  radiation.  In  certain  cases  the  variations  in  brightness  are 
nearly  as  regular  as  those  of  eclipsing  variables,  though  the  changes  are 
otherwise  quite  different.  In  other  cases  the  variations  in  brightness  are 
irregular  and  through  wide  ranges.  For  example,  the  star  Omicron  Ceti 
is  at  least  ten  thousand  times  brighter  at  its  highest  maxima  than  at  its 
lowest  minima.  .  .  . 

The  extreme  limit  in  variable  stars  is  reached  by  the  temporary  stars, 
or  novae.  These  stars  blaze  out  suddenly  from  obscurity  to  great  brilliance, 
in  some  cases  increasing  their  radiation  a  hundred-thousandfold  in  a  day 
or  two,  only  gradually  to  sink  back  to  relative  obscurity  within  a  few 
months.  A  number  of  these  remarkable  temporary  stars  have  played 
important  roles  in  the  history  of  astronomy.  For  example,  the  Greek 
philosopher  and  astronomer  Hipparchus  (about  160-105  B.C.)  made  the 
earliest  known  catalogue  of  stars,  1080  in  number,  in  order  to  determine 
whether  all  stars  are  as  transitory  as  the  nova  which  he  observed.  Another 
temporary  star  inspired  Tycho  Brahe  (1546-1601)  to  become  an  observer, 
and  another  which  appeared  in  1572  aroused  the  interest  of  Kepler  in 

We  do  not  know  the  cause  of  the  remarkable  outbursts  of  the  novae, 
which  are  more  violent  phenomena  on  a  stellar  scale  than  any  of  the  little 
explosions  which  ever  take  place  on  the  earth  or  even  than  the  much 
greater  ones  on  the  sun.  If  our  sun  should  ever  become  a  temporary  star, 
our  earth  and  the  other  planets  would  be  quickly  destroyed.  It  seems 
probable,  however,  that  only  certain  stars  are  subject  to  these  mighty 
outbursts,  and  that  they  occur  again  and  again,  separated  by  long  intervals. 
These  cataclysmic  phenomena  teach  us  how  little  we  know  of  violent 
forces,  even  when  we  observe  enormous  volumes  of  incandescent  gases 
shoot  up  hundreds  of  thousands  of  miles  from  the  surface  of  the  sun. 


There  are  among  the  stars  many  faint,  hazy  patches  called  nebulae,  or 
little  clouds.  Some  of  them,  such  as  that  around  the  central  star  in  the 
Sword  of  Orion,  are  faintly  visible  to  the  unaided  eye,  but  most  of  them 
are  found  only  with  telescopic  aid  or  by  photography.  They  look  like 
tenuous  gaseous  masses,  and  for  a  long  time  they  were  thought  to  be 
gaseous  in  nature,  perhaps  primordial  world  stuff  out  of  which  stars 
evolve  in  the  course  of  enormous  periods  of  time.  With  more  powerful 
telescopes,  however,  a  few  of  them  were  resolved  into  separate  stars. 


Then  for  a  time  it  was  supposed  that  probably  all  nebulae  are  swarms 
of  stars  which  can  be  resolved  by  sufficiently  powerful  instruments.  But 
toward  the  close  of  the  nineteenth  century  this  conjecture  was  proved  by 
the  spectroscope  to  be  false,  for  when  their  light  was  examined  by  this  in- 
strument it  was  found  to  have  the  properties  of  light  radiated  by  luminous 
gases  rather  than  by  relatively  dense  stars.  Consequently,  we  now  know 
that  the  nebulae,  except  those  which  are  now  classed  differendy,  are 
tenuous  gases.  . .  . 


We  have  found  that  our  earth  is  a  member  of  a  family  of  planets.  Now 
we  inquire  whether  our  sun  is  similarly  a  member  of  a  family  of  stars. 

When  we  attempt  to  determine  whether  the  stars  are  the  components 
of  some  vast  organism,  we  are  at  once  confronted  with  serious  difficulties 
because  of  their  great  distances  apart.  For  example,  the  distance  between 
our  solar  system  and  the  nearest  known  star,  the  far  southern  Alpha 
Centauri,  is  4.3  light-years,  or  more  than  25,000,000,000,000  miles.  The 
nearest  bright  star  visible  from  northern  latitudes  is  Sirius  at  a  distance 
of  8.8  light-years.  Most  of  the  stars  within  the  range  of  the  unaided  eye 
are  many  times  as  far  away  as  Sirius,  while  most  of  those  photographed 
with  large  telescopes  are  distant  more  than  a  thousand  light-years.  .  .  . 

Let  us  first  consider  the  stellar  density  near  the  present  position  of  the 
solar  system  where  the  results  are  most  trustworthy.  Since  it  is  possible 
with  modern  instruments  and  photographic  processes  to  measure  with 
much  precision  the  distances  of  stars  within  thirteen  light-years  (76,000,- 
000,000,000  miles)  of  the  sun,  we  shall  first  examine  this  region  around 
the  sun.  Within  this  sphere  of  thirteen  light-years  in  radius  there  are  thirty 
known  stars,  five  of  which  are  doubles  and  one  of  which  is  a  triple.  It 
would  be  natural  to  expect  that  these  relatively  near  stars  would  be  in- 
cluded among  the  hundred  brightest  stars  in  the  sky.  As  a  matter  of  fact, 
only  six  of  them,  besides  the  sun,  are  bright  enough  to  be  visible  without 
optical  aid,  while  several  of  them  are  of  such  low  luminosity  that  they  are 
very  faint  in  spite  of  their  small  distance  from  us,  astronomically  speaking. 
Since  several  of  these  near  faint  stars  are  of  recent  discovery,  it  is  probable 
that  there  are  a  few  others,  at  present  unknown,  which  are  within  thirteen 
light-years  of  our  sun.  For  the  sake  of  having  a  definite  number  to  serve 
as  a  basis  for  our  calculations,  we  shall  assume  that  there  are  thirty-five 
stars  within  this  sphere.  .  .  . 

It  should  not  be  understood  that  the  thirty-five  stars  we  are  considering 
form  a  system  in  any  special  sense.  They  are  simply  a  small  sample  out 
of  an  ocean  of  stars  and  give  us  some  idea  respecting  what  the  general 


stellar  system  is  like.  At  present  the  stars  in  this  sphere  arc  near  one 
another,  but  their  neighborliness  is  only  transitory,  for  they  are  moving  in 
various  directions  at  various  velocities,  and  their  mutual  gravitation  lacks 
much  of  being  sufficient  to  hold  them  together.  In  a  million  years  they 
will  be  far  from  one  another  and  will  have  formed  entirely  different  close 

There  are,  however,  families  of  stars  in  the  sense  that  they  permanently, 
or  at  least  for  millions  of  millions  of  years,  form  a  dynamical  system  of 
mutually  interacting  bodies.  The  best-known  of  such  families  is  the 
Hyades  stars  in  the  constellation  Taurus.  About  eighty  of  these  stars  are 
moving  together  through  the  celestial  regions  like  a  flock  of  migratory 
birds  across  the  sky.  Their  spectra  prove  that  they  are  similar  in  constitu- 
tion, they  undoubtedly  had  a  common  origin,  and  they  are  undergoing 
parallel  evolutions. . . . 

There  are  several  hundred  other  known  clusters  of  stars  besides  the 
Hyades  family.  Some  of  them  are  open  groups  like  the  Big  Dipper  and 
the  Sickle  in  Leo.  Others  are  more  closely  related  families  like  the  Pleiades, 
and  in  a  few  clusters  the  stars  appear  to  be  actually  crowded  together, 
although  those  which  are  nearest  each  other  are  rarely  separated  by  less 
than  a  light-year.  .  .  . 

Our  sun  does  not  appear  to  be  a  member  of  a  compact  (in  the  astronom- 
ical sense)  family  of  stars,  but  it  is  a  member  of  an  enormous  star  cloud 
containing  millions  of  stars.  In  these  larger  organizations  the  stars  do 
not  exhibit  the  similarities  which  are  found  among  the  stars  of  such 
compact  families  as  the  Hyades.  Nor  are  they  moving  in  parallel  lines  at 
the  same  speed.  They  consist,  rather,  of  stars  of  all  classes  and  kinds, 
moving  around  among  one  another  somewhat  like  bees  in  a  swarm, 
doubtless  held  loosely  together  by  their  mutual  gravitation.  These  great 
star  clouds  largely  make  up  the  Milky  Way.  Even  with  the  unaided  eye 
they  loom  up  conspicuously,  under  favorable  conditions,  in  Cygnus, 
Sagittarius  and  Scorpius.  With  a  photographic  telescope  their  soft  mist 
is  resolved  into  myriads  of  stars.  .  .  . 

When  we  pass  beyond  the  star  cloud  of  which  the  sun  is  a  member,  we 
arrive  at  our  entire  Milky  Way  system,  or  galaxy.  It  is  composed  of  vast 
clouds  of  stars  and  millions  of  individual  stars  spread  out  in  the  form 
of  a  disk,  the  diameter  of  which  is  of  the  order  of  60,000  light-years  and 
the  thickness  of  which  is  perhaps  one  eighth  as  great.  It  is  not  to  be  under- 
stood that  our  galaxy  is  homogeneous  with  well-defined  exterior  surfaces. 
It  is,  rather,  a  somewhat  irregular  assemblage  of  star  clouds  and  individual 
stars,  with  vast  regions  of  relatively  high  steller  density,  always  decreasing, 
however,  toward  its  borders.  If  the  average  stellar  density  of  the  galactic 


system  were  as  great  as  it  is  within  thirteen  light-years  of  the  sun,  there 
would  be  in  our  galaxy  more  than  50,000,000,000  stars.  Although  this 
number  may  be  somewhat  too  large,  it  is  probable  that  there  are  several 
billion  stars  in  our  Milky  Way  system,  and  the  number  of  them  may 
exceed  even  fifty  billions.  It  is  interesting  that  heretofore  estimates  of 
astronomers  have  always  fallen  short  of  the  actualities,  as  have  conjectures 
in  other  fields  of  science. 

If  the  solar  system  were  at  the  center  of  the  galaxy,  the  stars  would  be 
symmetrically  distributed  around  the  Milky  Way.  The  stars  are,  however, 
much  more  numerous  in  the  direction  of  Sagittarius  and  Scorpius  than  in 
the  opposite  part  of  the  heavens.  This  fact  means  that  the  galactic  center 
is  in  the  direction  of  these  constellations,  perhaps  at  a  distance  of  a  few 
thousand  light-years.  Moreover,  the  sun  is  some  distance,  perhaps  a  few 
hundred  light-years,  north  of  the  central  plane  of  the  galaxy,  a  result 
which  is  inferred  from  the  observed  fact  that  stars  are  somewhat  more 
numerous  on  the  south  side  than  they  are  on  the  north  side  of  the  great 
circle  representing,  at  least  generally,  its  central  line.  This  is  the  position 
of  the  solar  system  at  present,  but  the  sun  is  moving  obliquely  northward 
from  the  galactic  plane  at  the  rate  of  a  light-year  in  fifteen  or  twenty 
thousand  years.  Consequently,  if  it  maintains  its  velocity  and  direction 
of  motion  for  a  million  years,  it  will  then  be  in  a  substantially  different 
part  of  our  galaxy. 

Our  stellar  system  owes  its  disklike  shape  to  its  rotation,  an  inference 
which  is  based  on  dynamical  principles  and  which  has  been  verified  by 
observations.  Astronomers  long  ago  proved  the  revolution  of  the  earth 
around  the  sun  by  observations  of  the  distant  stars.  Now  they  are  proving 
the  rotation  of  the  enormous  galaxy  by  measurements  of  velocities  toward 
or  from  systems  of  stars  far  beyond  its  borders.  ...  In  spite  of  all  the 
variety  in  the  motions  of  its  stars  and  star  clouds,  it  on  the  whole  is 
involved  in  an  immense  gyration.  At  the  distance  of  the  sun  from  its 
center  the  velocity  of  its  rotation  is  probably  of  the  order  of  one  or  two 
hundred  miles  per  second,  and  the  period  of  its  rotation  between  fifty  and 
two  hundred  million  years.  It  follows  that  during  the  long  intervals  of 
the  geological  eras  our  earth  in  its  motion  with  the  sun  has  traveled 
widely  throughout  our  galactic  system.  .  .  . 


Somewhat  outside  of  our  galactic  system,  at  distances  ranging  from 
25,000  to  160,000  light-years,  there  are  approximately  a  hundred  great 
aggregations  of  stars  which  are  called  globular  dusters  because  they  are 
almost  exactly  spherical  in  iorm.  At  the  distances  of  these  clusters  only 


giant  and  supergiant  stars  are  separately  visible  even  through  large  tele- 
scopes. Consequently,  those  of  their  stars  which  are  observed  or  photo- 
graphed as  separate  objects  are  only  a  very  small  fraction  of  all  the  stars 
which  they  contain.  Yet  the  separately  observed  stars  in  the  globular 
clusters  are  numbered  by  thousands  and  tens  of  thousands,  and  the  fainter 
ones  almost  certainly  number  hundreds  of  thousands  and  probably 

One  of  the  few  globular  clusters  visible  to  the  unaided  eye  is  the  Great 
Cluster  in  Hercules.  At  its  distance  of  33,000  light-years  the  combined 
light  of  400,000  stars,  each  equal  to  our  sun  in  luminosity,  would  be  hardly 
visible  to  the  unaided  eye.  Hence  this  cluster  must  be  composed  of  an 
enormous  number  of  stars  and  many  of  high  luminosity.  Indeed,  on  a 
photograph  of  it  taken  with  one  of  the  great  telescopes  on  Mount  Wilson, 
the  images  of  40,000  stars  were  counted,  the  faintest  of  these  stars  being 
approximately  a  hundred  times  as  luminous  as  our  sun.  Consequently, 
there  can  be  little  doubt  that  this  immense  system  contains  at  least  a 
million  stars  as  great  as  our  sun,  and  probably  many  millions  of  lower 
luminosity.  Yet  it  is  so  far  away  in  the  depths  of  space  that  we  receive 
from  all  its  millions  of  suns  less  than  one  sixth  as  much  light  as  we 
receive  from  the  North  Star. 

.  .  .  Assume  that  the  Hercules  cluster  contains  a  hundred  thousand 
giant  and  supergiant  stars  and  a  million  stars  altogether.  We  find  from 
its  distance  and  its  apparent  diameter  that  its  actual  diameter  is  about 
one  hundred  light-years.  Hence  it  follows  that  if  its  hundred  thousand 
great  stars  were  uniformly  distributed  throughout  its  volume,  the  average 
distance  between  those  which  are  adjacent  would  be  more  than  two  light- 
years,  or  about  140,000  times  the  distance  from  the  sun  to  the  earth.  If 
we  include  the  million  stars  in  our  computation,  we  find  that  the  average 
distance  between  neighbors  is  about  one  light-year.  .  .  .  Even  the  giant 
stars  in  the  clusters  are  no  brighter  as  seen  from  one  another  than  Venus 
is  as  observed  from  the  earth. 

The  globular  clusters  are  dynamically  mature;  that  is,  they  have 
arrived  at  a  state  in  which  as  a  whole  they  remain  unchanged,  although 
their  individual  stars  are  in  ceaseless  motion.  Since  many  other  aggre- 
gations of  stars,  such  as  our  galaxy  and  its  star  clouds,  are  very  irregular 
in  structure,  it  does  not  seem  probable  that  the  globular  clusters  have 
always  had  their  present  perfect  symmetries.  Perhaps  better  support  for 
our  opinion  that  the  stars  in  them  were  once  irregularly  distributed  is 
found  in  the  exterior  galaxies  which  are  usually,  but  not  always,  far  from 

If  the  present  nearly  spherical  forms  of  the  globular  clusters  are  due 


to  dynamical  evolutions,  we  may  inquire  how  great  must  have  been  the 
interval  o£  time  between  some  earlier,  heterogeneous  state  and  their  present 
conditions.  We  first  find  the  astonishing  result  that  the  period  of  the 
circuit  of  a  star  around  the  Hercules  cluster,  or  from  near  its  exterior 
deep  into  its  interior  and  out  again  somewhere  else,  is  of  the  order  of  ten 
million  years.  We  next  note  that  the  dynamical  evolution  which  we  are 
considering  is  due  primarily  to  the  near  approaches  of  the  stars,  just  as 
the  uniform  distribution  of  molecules  of  various  kinds  in  a  gas  is  due 
primarily  to  their  collisions  which  occur  with  great  frequency;  indeed, 
on  the  average,  five  thousand  million  times  a  second. 

The  distances  between  the  stars  in  the  clusters  are  so  great  that,  on  the 
average,  a  star  will  make  ten  thousand  circuits  before  it  will  pass  near 
enough  another  star  to  have  the  direction  of  its  motion  changed  by  as 
much  as  twenty  degrees.  That  is,  on  the  average  it  moves  for  a  hundred 
thousand  million  years  (ten  thousand  times  ten  million  years)  as  though 
the  mass  of  the  cluster  were  not  concentrated  into  stars.  Then  it  passes  so 
near  one  of  these  concentrations  of  mass  (one  of  the  stars)  that  the 
direction  of  its  motion  is  appreciably  changed.  After  a  very  large  number, 
perhaps  a  million,  of  these  adventures  all  the  earlier  heterogeneities  are 
smoothed  out  with  a  resulting  globular  cluster  of  stars.  That  is,  the  very 
organization  of  the  globular  clusters  proves  that  these  spherical  masses 
of  stars  have  been  undergoing  independent  evolutions  for  at  least  millions 
of  millions  of  years.  In  the  course  of  time,  however,  these  symmetrical 
structures  may  pass  near  or  through  somewhat  similar  aggregations  and 
be  transformed  into  spinning  irregular  spirals  similar  to  our  galaxy, 


We  have  often  called  the  Milky  Way  system  of  stars  "our"  galaxy,  as 
though  it  were  something  we  possess,  or  which  is  at  least  in  our  immediate 
neighborhood.  From  the  standpoint  of  the  earth  or  even  of  the  whole  solar 
system  our  language  has  been  presumptuous,  for  we  have  explored  tens 
of  thousands  of  light-years,  or  hundreds  of  millions  of  times  the  distance 
from  our  planet  to  the  sun.  .  .  .  But  all  these  objects  are  of  secondary 
importance  and  interest  in  comparison  with  the  enormous  galaxy  known 
as  the  Great  Nebula  in  Andromeda.  Until  within  a  few  years  astronomers 
gazed  up  at  this  hazy  patch  of  light,  which  is  just  within  the  range  of 
the  unaided  eye,  and  thought  they  were  looking  only  at  a  tenuous  nebula 
lying  out  toward  the  borders  of  our  stellar  system.  Now  they  know  that 
what  they  have  been  seeing  is  a  great  exterior  galaxy,  which  in  magnitude, 
in  number  of  stars,  and  in  structure  is  similar  to  our  own. 

The  distance  from  our  present  position  to  the  Great  Nebula  in  An- 


dromeda  is  about  900,000  light-years.  Consequently,  we  see  this  galaxy 
not  as  it  is  now  but  as  it  was  before  our  ancestors  evolved  to  the  level 
of  men.  .  .  .  The  so-called  Andromeda  nebula  is  actually  a  galaxy  in 
every  essential  respect  similar  to  our  own,  a  much  flattened  disk  of  many 
billions  of  stars,  having  a  diameter  of  something  like  80,000  light-years 
and  rotating  in  a  period  of  perhaps  150,000,000  years. 

There  are  within  a  million  light-years  of  the  solar  system  six  known 
galaxies,  including  our  own.  But  outside  of  this  great  sphere  there  are 
hundreds  of  thousands  of  other  galaxies  within  easy  reach  of  large  photo- 
graphic telescopes.  .  .  . 

From  atoms  to  galaxies  each  physical  unit  is  made  up  of  smaller  units — 
atoms  of  protons  and  electrons,  molecules  of  atoms,  stars  of  molecules, 
galaxies  of  stars.  We  naturally  inquire  whether  the  galaxies  we  observe 
are  not  components  of  still  greater  cosmic  units;  whether  our  Milky  Way 
system,  for  example,  the  Magellanic  Clouds,  the  Andromeda  galaxy  and 
others  which  are  relatively  near  are  not  the  constituents  of  a  supergalaxy 
enormously  greater  than  any  one  of  them,  and  perhaps  millions  of  light- 
years  in  diameter.  Although  the  field  which  we  are  considering  is  rela- 
tively new,  astronomers  have  already  found  numerous  aggregations  of 
galaxies  into  supergalaxies.  For  example,  Harlow  Shapley  has  described 
a  supergalaxy  in  the  direction  of  Centaurus,  but  a  hundred  and  fifty 
million  light-years  beyond  the  stars  of  this  constellation,  which  is  com- 
posed of  more  than  three  hundred  galaxies,  all  of  which  are  probably 
comparable  to  our  own  steller  system.  The  space  occupied  by  this  super- 
galaxy  is  an  oval  about  seven  million  light-years  in  length  and  two  million 
light-years  in  diameter.  It  is  so  vast  that  the  average  distance  between 
those  of  its  galaxies  which  are  adjacent  is  approximately  a  million  light- 

What  is  beyond  the  supergalaxies?  There  is  no  observational  evidence 
bearing  upon  the  question.  There  are  good  theoretical  reasons,  however, 
for  concluding  that  they  do  not  extend  on  through  an  infinite  space  with 
the  approximate  frequency  which  is  found  within  a  few  hundred  million 
light-years  of  our  own  galaxy.  According  to  certain  deductions  from  the 
theory  of  relativity  they  are  limited  in  number,  and  space  itself  is  limited 
in  extent.  On  the  other  hand,  the  supergalaxies  which  we  now  know 
may  be  the  component  units  of  enormously  greater  supergalaxies  of  the 
second  order.  And  these  supergalaxies  of  the  second  order  may  be  the 
constituents  of  supergalaxies  of  the  third  order,  and  so  on  upward  in  an 
unending  sequence.  And,  just  as  molecules  are  composed  of  atoms,  and 
atoms  of  protons  and  electrons,  so  protons  and  electrons  may  be  made  up 


of  still  smaller  units,  and  so  on  downward  in  an  unending  sequence  of 

Naturally,  it  is  unsafe  to  draw  any  positive  conclusions  respecting  super- 
galaxies  of  higher  order  or  respecting  subelectrons,  for  direct  evidence 
is  lacking  and  we  can  reason  only  by  analogy.  It  is  even  more  hazardous 
to  speculate  regarding  a  creation  of  the  physical  universe,  for  observa- 
tional evidence  is  equally  lacking,  and  there  is  not  even  analogy  as  a 
guide.  Consequently,  though  science  has  placed  us  on  an  eminence  from 
which  we  see  very  far,  beyond  our  horizon  there  still  lies  a  challenging 

Is  There  Life  on  Other  Worlds? 


*^  center  of  the  universe  the  question  of  life  on  other  worlds  could 
hardly  arise;  there  were  no  other  worlds  in  the  astronomical  sense,  although 
a  heaven  above  and  a  hell  beneath  might  form  adjuncts  to  this  world. 
The  cosmology  of  the  Divina  Commedia  is  typical  of  its  period.  In  1440 
we  find  Nicholas  of  Cusa  comparing  our  earth,  as  Pythagoras  had  done 
before  him,  to  the  other  stars,  although  without  expressing  any  opinion  as 
to  whether  these  other  stars  were  inhabited  or  not.  At  the  end  of  the  next 
century  Giordano  Bruno  wrote  that  "there  are  endless  particular  worlds 
similar  to  this  of  the  earth."  He  plainly  supposed  these  other  worlds — "the 
moon,  planets  and  other  stars,  which  are  infinite  in  number" — to  be 
inhabited,  since  he  regarded  their  creation  as  evidence  of  the  Divine 
goodness.  He  was  burned  at  the  stake  in  1600;  had  he  lived  only  ten  years 
longer,  his  convictions  would  have  been  strengthened  by  Galileo's  discovery 
of  mountains  and  supposed  seas  on  the  moon. 
The  arguments  of  Kepler  and  Newton  led  to  a  general  recognition  that 


the  stars  were  not  other  worlds  like  our  earth  but  other  suns  like  our  sun. 
When  once  this  was  accepted  it  became  natural  to  imagine  that  they  also 
were  surrounded  by  planets  and  to  picture  each  sun  as  showering  life-sus- 
taining light  and  heat  on  inhabitants  more  or  less  like  ourselves.  In  1829 
a  New  York  newspaper  scored  a  great  journalistic  hit  by  giving  a  vivid, 
but  wholly  fictitious,  account  of  the  activities  of  the  inhabitants  of  the 
moon  as  seen  through  the  telescope  recently  erected  by  His  Majesty's 
Government  at  the  Cape. 

It  would  be  a  long  time  before  we  could  see  what  the  New  York  paper 
claimed  to  see  on  the  moon — batlike  men  flying  through  the  air  and 
inhabiting  houses  in  trees — even  if  it  were  there  to  see.  To  see  an  object 
of  human  size  on  the  moon  in  detail  we  should  need  a  telescope  of  from 
10,000  to  a  100,000  inches  aperture,  and  even  then  we  should  have  to  wait 
years,  or  more  probably  centuries,  before  the  air  was  still  and  clear  enough 
for  us  to  see  details  of  human  size. 

To  detect  general  evidence  of  life  on  even  the  nearest  of  the  planets 
would  demand  far  larger  telescopes  than  anything  at  present  in  existence, 
unless  this  evidence  occupied  an  appreciable  fraction  of  the  planet's  surface. 
The  French  astronomer  Flammarion  once  suggested  that  if  chains  of  light 
were  placed  on  the  Sahara  on  a  sufficiently  generous  scale,  they  might  be 
visible  to  Martian  astronomers  if  any  such  there  be.  If  this  light  were 
placed  so  as  to  form  a  mathematical  pattern,  intelligent  Martians  might 
conjecture  that  there  was  intelligent  life  on  earth.  Flammarion  thought 
that  the  lights  might  suitably  be  arranged  to  illustrate  the  theorem  of 
Pythagoras  (Euclid,  i.  47).  Possibly  a  better  scheme  would  be  a  group  of 
searchlights  which  could  emit  successive  flashes  to  represent  a  series  of 
numbers.  If,  for  instance,  the  numbers  3,  5,  7,  n,  13,  17,  19,  23  ...  (the 
sequence  of  primes)  were  transmitted,  the  Martians  might  surely  infer  the 
existence  of  intelligent  Tellurians.  But  any  visual  communication  between 
planets  would  need  a  combination  of  high  telescopic  power  at  one  end 
and  of  engineering  works  on  a  colossal,  although  not  impossible,  scale  at 
the  other. 

Some  astronomers — mainly  in  the  past — have  thought  that  the  so-called 
canals  on  Mars  provided  evidence  of  just  this  kind,  although  of  course 
unintentionally  on  the  part  of  the  Martians.  Two  white  patches  which 
surround  the  two  poles  of  Mars  are  observed  to  increase  and  decrease  with 
the  seasons,  like  our  terrestrial  polar  ice.  Over  the  surface  of  Mars  some 
astronomers  have  claimed  to  see  a  geometrical  network  of  straight  lines, 
which  they  have  interpreted  as  a  system  of  irrigation  canals,  designed  to 
bring  melted  ice  from  these  polar  caps  to  parched  equatorial  regions. 
Percival  Lowell  calculated  that  this  could  be  done  by  a  pumping  system 


of  4,000  times  the  power  of  Niagara.  It  is  fairly  certain  now  that  the  polar 
caps  are  not  of  ice,  but  even  if  they  were,  the  radiation  of  the  summer  sun 
on  Mars  is  so  feeble  that  it  could  not  melt  more  than  a  very  thin  layer  of 
ice  before  the  winter  cold  came  to  freeze  it  solid  again.  Actually  the  caps 
are  observed  to  change  very  rapidly  and  are  most  probably  clouds  con- 
sisting of  some  kind  of  solid  particles. 

The  alleged  canals  cannot  be  seen  at  all  in  the  largest  telescopes  nor 
can  they  be  photographed,  but  there  are  technical  reasons  why  neither  of 
these  considerations  is  conclusive  against  the  existence  of  the  canals.  A 
variety  of  evidence  suggests,  however,  that  the  canals  are  mere  subjective 
illusions — the  result  of  overstraining  the  eyes  in  trying  to  see  every  detail 
of  a  never  very  brightly  illuminated  surface.  Experiments  with  school  chil- 
dren have  shown  that  under  such  circumstances  the  strained  eye  tends  to 
connect  patches  of  color  by  straight  lines.  This  will  at  least  explain  why 
various  astronomers  have  claimed  to  see  straight  lines  not  only  on  Mars, 
where  it  is  just  conceivable  that  there  might  be  canals,  but  also  on  Mercury 
and  the  largest  satellite  of  Jupiter,  where  it  seems  beyond  the  bounds  of 
possibility  that  canals  could  have  been  constructed,  as  well  as  on  Venus,  on 
which  real  canals  could  not  possibly  be  seen  since  its  solid  surface  is  entirely 
hidden  under  clouds.  It  may  be  significant  that  E.  E.  Barnard,  perhaps  the 
most  skilled  observer  that  astronomy  has  ever  known,  was  never  able  to 
see  the  canals  at  all,  although  he  studied  Mars  for  years  through  the  largest 

A  more  promising  line  of  approach  to  our  problem  is  to  examine  which, 
if  any,  of  the  planets  is  physically  suitable  for  life.  But  we  are  at  once  con- 
fronted with  the  difficulty  that  we  do  not  know  what  precise  conditions 
are  necessary  for  life.  A  human  being  transferred  to  the  surface  of  any 
one  of  the  planets  or  of  their  satellites,  would  die  at  once,  and  this  for 
several  different  reasons  on  each.  On  Jupiter  he  would  be  simultaneously 
frozen,  asphyxiated,  and  poisoned,  as  well  as  doubly  pressed  to  death  by 
his  own  weight  and  by  an  atmospheric  pressure  of  about  a  million  terres- 
trial atmospheres.  On  Mercury  he  would  be  burned  to  death  by  the  sun's 
heat,  killed  by  its  ultra-violet  radiation,  asphyxiated  from  want  of  oxygen, 
and  desiccated  from  want  of  water.  But  this  does  not  touch  the  question 
of  whether  other  planets  may  not  have  developed  species  of  life  suited  to 
their  own  physical  conditions.  When  we  think  of  the  vast  variety  of  con- 
ditions under  which  terrestrial  life  exists  on  earth — plankton,  soil  bacteria, 
stone  bacteria,  and  the  great  variety  of  bacteria  which  are  parasitic  on  the 
higher  forms  of  life — it  would  seem  rash  to  suggest  that  there  are  any 
physical  conditions  whatever  to  which  life  cannot  adapt  itself.  Yet  as  the 
physical  states  of  other  planets  are  so  different  from  that  of  our  own,  it 


seems  safe  to  say  that  any  life  there  may  be  on  any  of  them  must  be  very 
different  from  the  life  on  earth. 

The  visible  surface  of  Jupiter  has  a  temperature  of  about  — 138°  C, 
which  represents  about  248  degrees  of  frost  on  the  Fahrenheit  scale.  The 
planet  probably  comprises  an  inner  core  of  rock,  with  a  surrounding  layer 
of  ice  some  16,000  miles  in  thickness,  and  an  atmosphere  which  again  is 
several  thousands  of  miles  thick  and  exerts  the  pressure  of  a  million 
terrestrial  atmospheres  which  we  have  already  mentioned.  The  only  known 
constituents  of  this  atmosphere  are  the  poisonous  gases  methane  and 
ammonia.  It  is  certainly  hard  to  imagine  such  a  planet  providing  a  home 
for  life  of  any  kind  whatever.  The  planets  Saturn,  Uranus,  Neptune,  and 
Pluto,  being  farther  from  the  sun,  are  almost  certainly  even  colder  than 
Jupiter  and  in  all  probability  suffer  from  at  least  equal  disabilities  as 
abodes  of  life. 

Turning  sunward  from  these  dismal  planets,  we  come  first  to  Mars, 
where  we  find  conditions  much  more  like  those  of  our  own  planet.  The 
average  temperature  is  about  —40°  C.,  which  is  also  —40°  on  the  Fahren- 
heit scale,  but  the  temperature  rises  above  the  freezing  point  on  summer 
afternoons  in  the  equatorial  regions.  The  atmosphere  contains  at  most 
only  small  amounts  of  oxygen  and  carbon  dioxide,  perhaps  none  at  all,  so 
that  there  can  be  no  vegetation  comparable  with  that  of  the  earth.  The 
surface,  in  so  far  as  it  can  be  tested  by  a  study  of  its  powers  of  reflection 
and  polarization,  appears  to  consist  of  lava  and  volcanic  ash.  To  us  it  may 
not  seem  a  promising  or  comfortable  home  for  life,  but  life  of  some  kind 
or  other  may  be  there  nevertheless. 

Being  at  the  same  average  distance  from  the  sun  as  the  earth,  the  moon 
has  about  the  same  average  temperature,  but  the  variations  around  this 
average  temperature  are  enormous,  the  equatorial  temperature  varying 
roughly  from  120°  C.  to  —  80°  C.  The  telescope  shows  high  ranges  of 
mountains,  apparently  volcanic,  interspersed  with  flat  plains  of  volcanic 
ash.  The  moon  has  no  atmosphere  and  consequently  no  water;  it  shows 
no  signs  of  life  or  change  of  any  kind,  unless  perhaps  for  rare  falls  of 
rock  such  as  might  result  from  the  impact  of  meteors  falling  in  from  outer 
space.  A  small  town  on  the  moon,  perhaps  even  a  large  building,  ought  to 
be  visible  in  our  largest  telescopes,  but,  needless  to  say,  we  see  nothing  of 
the  kind. 

Venus,  the  planet  next  to  the  earth,  presents  an  interesting  problem. 
It  is  similar  to  the  earth  in  size  but  being  nearer  the  sun  is  somewhat 
warmer.  As  it  is  blanketed  in  cloud  we  can  only  guess  as  to  the  nature  of 
its  surface.  But  its  atmosphere  can  be  studied  and  is  found  to  contain 
little  or  no  oxygen,  so  that  the  planet's  surface  can  hardly  be  covered  with 


vegetation  as  the  surface  of  the  earth  is.  Indeed,  its  surface  is  probably  so 
hot  that  water  would  boil  away.  Yet  no  trace  of  water  vapor  is  found  in 
the  atmosphere,  so  that  the  planet  may  well  be  devoid  of  water.  There  are 
reasons  for  thinking  that  its  shroud  of  clouds  may  consist  of  solid  par- 
ticles, possibly  hydrates  of  formaldehyde.  Clearly  any  life  that  this  planet 
may  harbor  must  be  very  different  from  that  of  the  earth. 

The  only  planet  that  remains  is  Mercury.  This  always  turns  the  same 
face  to  the  sun  and  its  temperature  ranges  from  about  420°  C.  at  the  center 
of  this  face  to  unimaginable  depths  of  cold  in  the  eternal  night  of  the  face 
which  never  sees  the  sun.  The  planet  is  too  feeble  gravitationally  to  retain 
much  of  an  atmosphere  and  its  surface,  in  so  far  as  this  can  be  tested, 
appears  to  consist  mainly  of  volcanic  ash  like  the  moon  and  Mars.  Once 
again  we  have  a  planet  which  does  not  appear  promising  as  an  abode  of 
life  and  any  life  that  there  may  be  must  be  very  different  from  our  own. 

Thus  our  survey  of  the  solar  system  forces  us  to  the  conclusion  that  it 
contains  no  place  other  than  our  earth  which  is  at  all  suitable  for  life  at 
all  resembling  that  existing  on  earth.  The  other  planets  are  ruled  out 
largely  by  unsuitable  temperatures.  It  used  to  be  thought  that  Mars  might 
have  had  a  temperature  more  suited  to  life  in  some  past  epoch  when  the 
sun's  radiation  was  more  energetic  than  it  now  is,  and  that  similarly 
Venus  can  perhaps  look  forward  to  a  more  temperate  climate  in  some 
future  age.  But  these  possibilities  hardly  accord  with  modern  views  of 
stellar  evolution.  The  sun  is  now  thought  to  be  a  comparatively  unchanging 
structure,  which  has  radiated  much  as  now  through  the  greater  part  of  its 
past  life  and  will  continue  to  do  the  same  until  it  changes  cataclysmically 
into  a  minute  "white  dwarf"  star.  When  this  happens  there  will  be  a  fall 
of  temperature  too  rapid  for  life  to  survive  anywhere  in  the  solar  system 
and  too  great  for  new  life  ever  to  get  a  foothold.  As  regards  suitability  for 
life,  the  earth  seems  permanently  to  hold  a  unique  position  among  the 
bodies  surrounding  our  sun. 

Our  sun  is,  however,  only  one  of  myriads  of  stars  in  space.  Our  own 
galaxy  alone  contains  about  100,000  million  stars,  and  there  are  perhaps 
10,000  million  similar  galaxies  in  space.  Stars  are  about  as  numerous  in 
space  as  grains  of  sand  in  the  Sahara.  What  can  we  say  about  the  possibili- 
ties of  life  on  planets  surrounding  these  other  suns  ? 

We  want  first  to  know  whether  these  planets  exist.  Observational  astron- 
omy can  tell  us  nothing;  if  every  star  in  the  sky  were  surrounded  by  a 
planetary  system  like  that  of  our  sun,  no  telescope  on  earth  could  reveal  a 
single  one  of  these  planets.  Theory  can  tell  us  a  little  more.  While  there 
is  some  doubt  as  to  the  exact  manner  in  which  the  sun  acquired  its  family 
of  planets,  all  modern  theories  are  at  one  in  supposing  that  it  was  the 


result  of  the  close  approach  of  another  star.  Other  stars  in  the  sky  must 
also  experience  similar  approaches,  although  calculation  shows  that  such 
events  must  be  excessively  rare.  Under  conditions  like  those  which  now 
prevail  in  the  neighborhood  of  the  sun,  a  star  will  experience  an  approach 
close  enough  to  generate  planets  only  about  once  in  every  million  million 
million  years.  If  we  suppose  the  star  to  have  lived  under  these  conditions 
for  about  2,000  million  years,  only  one  star  in  500  million  will  have  expe- 
rienced the  necessary  close  encounter,  so  that  at  most  one  star  in  500 
million  will  be  surrounded  by  planets.  This  looks  an  absurdly  minute 
fraction  of  the  whole,  yet  when  the  whole  consists  of  a  thousand  million 
million  million  stars,  this  minute  fraction  represents  two  million  million 
stars.  On  this  calculation,  then  two  million  million  stars  must  already  be 
surrounded  by  planets  and  a  new  solar  system  is  born  every  few  hours. 
The  calculation  probably  needs  many  adjustments;  for  instance,  condi- 
tions near  our  sun  are  not  necessarily  typical  of  conditions  throughout 
space  and  the  conditions  of  today  are  probably  not  typical  of  conditions  in 
past  ages.  Indeed,  on  any  reasonable  view  of  stellar  evolution,  each  star 
must  have  begun  its  life  as  a  vast  mass  of  nebulous  gas,  in  which  state  it 
would  present  a  far  more  vulnerable  target  than  now  for  disruptive  attacks 
by  other  stars.  Detailed  calculation  shows  that  the  chance  of  a  star's 
producing  planets  in  this  early  stage,  although  not  large,  would  be  quite 
considerable,  and  suggests,  with  a  large  margin  to  spare,  that  although 
planetary  systems  may  be  rare  in  space,  their  total  number  is  far  from 
insignificant.  Out  of  the  thousands  or  millions  of  millions  of  planets  that 
there  must  surely  be  in  space,  a  very  great  number  must  have  physical 
conditions  very  similar  to  those  prevailing  on  earth. 

We  cannot  even  guess  whether  these  are  inhabited  by  life  like  our  own 
or  by  life  of  any  kind  whatever.  The  same  chemical  atoms  exist  there  as 
exist  here  and  must  have  the  same  properties,  so  that  it  is  likely  that  the 
same  inorganic  compounds  have  formed  there  as  have  formed  here.  If  so, 
we  would  like  to  know  how  far  the  chain  of  life  has  progressed,  but 
present-day  science  can  give  no  help.  We  can  only  wonder  whether  any 
life  there  may  be  elsewhere  in  the  universe  has  succeeded  in  managing  it* 
affairs  better  than  we  have  done  in  recent  years. 


The  Milky  Way  ana  Beyond 


begins  his  lecture  with  the  words  "Gentlemen,  you  have  seen  the  moon 
— or  at  least  heard  tell  of  it."  I  think  I  may  in  the  same  way  presume  that 
you  are  acquainted  with  the  Milky  Way,  which  can  be  seen  on  any  clear 
dark  night  as  a  faintly  luminous  band  forming  an  arch  from  horizon  to 
horizon.  The  telescopes  show  that  it  is  composed  of  multitudes  of  stars. 
One  is  tempted  to  say  "countless  multitudes";  but  it  is  part  of  the  business 
of  an  astronomer  to  count  them,  and  the  number  is  not  uncountable 
though  it  amounts  to  more  than  ten  thousand  millions.  The  number 
of  stars  in  the  Milky  Way  is  considerably  greater  than  the  number  of 
human  beings  on  the  earth.  Each  star,  I  may  remind  you,  is  an  immense 
fiery  globe  of  the  same  general  nature  as  our  sun. 

There  is  no  sharp  division  between  the  distant  stars  which  form  the 
Milky  Way  and  the  brighter  stars  which  we  see  strewn  over  the  sky. 
All  these  stars  taken  together  form  one  system  or  galaxy;  its  extent  is 
enormous  but  not  unlimited.  Since  we  are  situated  inside  it  we  do  not 
obtain  a  good  view  of  its  form;  but  we  are  able  to  see  far  away  in  space 
other  galaxies  which  also  consist  of  thousands  of  millions  of  stars,  and 
presumably  if  we  could  see  our  own  galaxy  from  outside,  it  would  appear 
like  one  of  them.  These  other  galaxies  are  known  as  "spiral  nebulae." 
We  believe  that  our  own  Milky  Way  system  is  more  or  less  like  them.  If  so, 
the  stars  form  a  flat  coil — rather  like  a  watch-spring — except  that  the  coil 
is  double. 

When  we  look  out  in  directions  perpendicular  to  the  plane  of  the 
coil,  we  soon  reach  the  limit  of  the  system;  but  in  the  plane  of  the  coil 
we  see  stars  behind  stars  until  they  become  indistinguishable  and  fade 
into  the  hazy  light  of  the  Milky  Way.  It  has  been  ascertained  that  we 
are  a  very  long  way  from  the  centre  of  our  own  galaxy,  so  that  there  are 
many  more  stars  on  one  side  of  us  than  on  the  other. 



Looking  at  one  of  these  galaxies,  it  is  impossible  to  resist  the  impression 
that  it  is  whirling  round— like  a  Catherine  Wheel.  It  has,  in  fact,  been 
possible  to  prove  that  some  of  the  spiral  nebulae  are  rotating,  and  to 
measure  the  rate  of  rotation.  Also  by  studying  the  motions  of  the  stars  in 
our  own  galaxy,  it  has  been  found  that  it  too  is  rotating  about  a  centre. 
The  centre  is  situated  a  long  way  from  us  in  the  constellation  Ophiuchus 
near  a  particularly  bright  patch  of  the  Milky  Way;  the  actual  centre  is, 
however,  hidden  from  us  by  a  cloud  of  obscuring  matter.  My  phrase, 
"whirling  round,"  may  possibly  give  you  a  wrong  impression.  With  these 
vast  systems  we  have  to  think  in  a  different  scale  of  space  and  time,  and 
the  whirling  is  slow  according  to  our  ordinary  ideas.  It  takes  about  300 
million  years  for  the  Milky  Way  to  turn  round  once.  But  after  all  that  is 
not  so  very  long.  Geologists  tell  us  that  the  older  rocks  in  the  earth's 
crust  were  formed  1300  million  years  ago;  so  the  sun,  carrying  with  it  the 
earth  and  planets,  has  made  four  or  five  complete  revolutions  round  the 
centre  of  the  galaxy  within  geological  times. 

The  stars  which  form  our  Milky  Way  system  show  a  very  wide  diver- 
sity. Some  give  out  more  than  10,000  times  as  much  light  and  heat  as 
the  sun;  others  less  than  i/iooth.  Some  are  extremely  dense  and  com- 
pact; others  are  extremely  tenuous.  Some  have  a  surface  temperature  as 
high  as  20,000  or  30,000°  C.;  others  not  more  than  3000°  C.  Some  are 
believed  to  be  pulsating — swelling  up  and  deflating  within  a  period  of  a 
few  days  or  weeks;  these  undergo  great  changes  of  light  and  heat  accom- 
panying the  expansion  and  collapse.  It  would  be  awkward  for  us  if  our 
sun  behaved  that  way.  A  considerable  proportion  (about  1/3  of  the  whole 
number)  go  about  in  pairs,  forming  "double  stars";  the  majority,  how- 
ever, are  bachelors  like  the  sun. 

But  in  spite  of  this  diversity,  the  stars  have  one  comparatively  uniform 
characteristic,  namely  their  mass,  that  is,  the  amount  of  matter  which 
goes  to  form  them.  A  range  from  1/5  to  5  times  the  sun's  mass  would 
cover  all  but  the  most  exceptional  stars;  and  the  general  run  of  the  masses 
is  within  an  even  narrower  range.  Among  a  hundred  stars  picked  at 
random  the  diversity  of  mass  would  not  be  greater  proportionately  than 
among  a  hundred  men,  women  and  children  picked  at  random  from  a 

Broadly  speaking,  a  big  star  is  big,  not  because  it  contains  an  excessive 
amount  of  material,  but  because  it  is  puffed  out  like  a  balloon;  and  a 
small  star  is  small  because  its  material  is  highly  compressed.  Our  sun, 
which  is  intermediate  in  this,  as  in  most  respects,  has  a  density  rather 
greater  than  that  of  water.  (The  sun  is  in  every  way  a  typical  middle-class 
star.)  The  two  extremes—the  extremely  rarefied  and  the  extremely  dense 


stars — are  especially  interesting.  We  find  stars  whose  material  is  as  tenuous 
as  a  gas.  The  well-known  star  Capella,  for  example,  has  an  average  density 
about  equal  to  that  of  air;  to  be  inside  Capella  would  be  like  being 
surrounded  by  air,  as  we  ordinarily  are,  except  that  the  temperature 
(which  is  about  5,000,000°  C)  is  hotter  than  we  are  accustomed  to.  Still 
more  extreme  are  the  red  giant  stars  Betelgeuse  in  Orion  and  Antares  in 
Scorpio.  To  obtain  a  star  like  Betelgeuse,  we  must  imagine  the  sun  swell- 
ing out  until  it  has  swallowed  up  Mercury,  Venus  and  the  Earth,  and 
has  a  circumference  almost  equal  to  the  orbit  of  Mars.  The  density  of 
this  vast  globe  is  that  of  a  gas  in  a  rather  highly  exhausted  vessel.  Betel- 
geuse could  be  described  as  "a  rather  good  vacuum." 

At  the  other  extreme  are  the  "white  dwarf  stars,  which  have  extrava- 
gantly high  density.  I  must  say  a  little  about  the  way  in  which  this  was 

Between  1916  and  1924  I  was  very  much  occupied  trying  to  understand 
the  internal  constitution  of  the  stars,  for  example,  finding  the  temperature 
in  the  deep  interior,  which  is  usually  ten  million  degrees,  and  making  out 
what  sort  of  properties  matter  would  have  at  such  high  temperatures. 
Physicists  had  recently  been  making  great  advances  in  our  knowledge  of 
atoms  and  radiation;  and  the  problem  was  to  apply  this  new  knowledge 
to  the  study  of  what  was  taking  place  inside  a  star.  In  the  end  I  obtained 
a  formula  by  which,  if  you  knew  the  mass  of  a  star,  you  could  calculate 
how  bright  it  ought  to  be.  An  electrical  engineer  will  tell  you  that  to 
produce  a  certain  amount  of  illumination  you  must  have  a  dynamo  of  a 
size  which  he  will  specify;  somewhat  analogously  I  found  that  for  a  star 
to  give  a  certain  amount  of  illumination  it  must  have  a  definite  mass 
which  the  formula  specified.  This  formula,  however,  was  not  intended 
to  apply  to  all  stars,  but  only  to  diffuse  stars  with  densities  corresponding 
to  a  gas,  because  the  problem  became  too  complicated  if  the  material 
could  not  be  treated  as  a  perfect  gas. 

Having  obtained  the  theoretical  formula,  the  next  thing  was  to  compare 
it  with  observation.  That  is  where  the  trouble  often  begins.  And  there 
was  trouble  in  this  case;  only  it  was  not  of  the  usual  kind.  The  observed 
masses  and  luminosities  agreed  with  the  formulae  all  right;  the  trouble 
was  that  they  would  not  stop  agreeing!  The  dense  stars  for  which  the 
formula  was  not  intended  agreed  just  as  well  as  the  diffuse  stars  for 
which  the  formula  was  intended.  This  surprising  result  could  only  mean 
that,  although  their  densities  were  as  great  as  that  of  water  or  iron,  the 
stellar  material  was  nevertheless  behaving  like  a  gas;  in  particular,  it 
was  compressible  like  an  ordinary  gas. 

We  had  been  rather  blind  not  to  have  foreseen  this.  Why  is  it  that  we 


can  compress  air,  but  cannot  appreciably  compress  water?  It  is  because 
in  air  the  ultimate  particles  (the  molecules)  are  wide  apart,  with  plenty 
of  empty  space  between  them.  When  we  compress  air  we  merely  pack 
the  molecules  a  bit  closer,  reducing  the  amount  of  vacant  space.  But  in 
water  the  molecules  are  practically  in  contact  and  cannot  be  packed  any 
closer.  In  all  substances  the  ordinary  limit  of  compression  is  when  the 
molecules  jam  in  contact;  after  that  we  cannot  appreciably  increase  the 
density.  This  limit  corresponds  approximately  to  the  density  of  the  solid 
or  liquid  state.  We  had  been  supposing  that  the  same  limit  would  apply 
in  the  interior  of  a  star.  We  ought  to  have  remembered  that  at  the  temper- 
ature of  millions  of  degrees  there  prevailing  the  atoms  are  highly  ionized, 
i.e.  broken  up.  An  atom  has  a  heavy  central  nucleus  surrounded  by  a 
widely  extended  but  insubstantial  structure  of  electrons — a  sort  of 
crinoline.  At  the  high  temperature  in  the  stars  this  crinoline  of  electrons 
is  broken  up.  If  you  are  calculating  how  many  dancers  can  be  accom- 
modated in  a  ball-room,  it  makes  a  difference  whether  the  ladies  wear 
crinolines  or  not.  Judging  by  the  crinolined  terrestrial  atoms  we  should 
reach  the  limit  of  compression  at  densities  not  much  greater  than  water; 
but  the  uncrinolined  stellar  atoms  can  pack  much  more  densely,  and  do 
not  jam  together  until  densities  far  beyond  terrestrial  experience  are 

This  suggested  that  there  might  exist  stars  of  density  greater  than  any 
material  hitherto  known,  which  called  to  mind  a  mystery  concerning  the 
Companion  of  Sirius.  The  dog-star  Sirius  has  a  faint  companion  close 
to  it,  visible  in  telescopes  of  moderate  power.  There  is  a  method  of  finding 
densities  of  stars  which  I  must  not  stop  to  explain.  The  method  is  rather 
tentative;  and  when  it  was  found  to  give  for  the  Companion  of  Sirius 
a  density  50,000  times  greater  than  water,  it  was  naturally  assumed  that 
it  had  gone  wrong  in  its  application.  But  in  the  light  of  the  foregoing 
discussion,  it  now  seemed  possible  that  the  method  had  not  failed,  and 
that  the  extravagantly  high  density  might  be  genuine.  So  astronomers 
endeavoured  to  check  the  determination  of  density  by  another  method 
depending  on  Einstein's  relativity  theory.  The  second  method  confirmed 
the  high  density,  and  it  is  now  generally  accepted.  The  stuff  of  the 
Companion  of  Sirius  is  2000  times  as  dense  as  platinum.  Imagine  a 
match-box  filled  with  this  matter.  It  would  need  a  crane  to  lift  it — it 
would  weigh  a  ton. 

I  am  afraid  that  what  I  have  to  say  about  the  stars  is  largely  a  matter 
of  facts  and  figures.  There  is  only  one  star  near  enough  for  us  to  study 
its  surface,  namely  our  sun.  Ordinary  photographs  of  the  sun  show  few 
features,  except  the  dark  spots  which  appear  at  times.  But  much  more 


interesting  photographs  are  obtained  by  using  a  spectro-heliograph,  which 
is  an  instrument  blind  to  all  light  except  that  of  one  particular  wave 
length — coming  from  one  particular  kind  of  atom. 

Now  let  us  turn  to  the  rest  of  the  universe  which  lies  beyond  the  Milky 
Way.  Our  galaxy  is,  as  it  were,  an  oasis  of  matter  in  the  desert  of  empti- 
ness, an  island  in  the  boundless  ocean  of  space.  From  our  own  island  we 
see  in  the  far  distance  other  islands — in  fact  a  whole  archipelago  of 
islands  one  beyond  another  till  our  vision  fails.  One  of  the  nearest  of 
diem  can  actually  be  seen  with  the  naked  eye;  it  is  in  the  constellation 
Andromeda,  and  looks  like  a  faint,  rather  hazy,  star.  The  light  which 
we  now  see  has  taken  900,000  years  to  reach  us.  When  we  look  at  that 
faint  object  in  Andromeda  we  are  looking  back  900,000  years  into  the 
past.  Some  of  the  telescopic  spiral  nebulae  are  much  more  distant.  The 
most  remote  that  has  yet  been  examined  is  300,000,000  light-years  away. 

These  galaxies  are  very  numerous.  From  sample  counts  it  is  found 
that  more  than  a  million  of  them  are  visible  in  our  largest  telescopes;  and 
there  must  be  many  more  fainter  ones  which  we  do  not  see.  Our  sun 
is  just  one  star  in  a  system  of  thousands  of  millions  of  stars;  and  that 
whole  system  is  just  one  galaxy  in  a  universe  of  thousands  of  millions 
of  galaxies. 

Let  us  pause  to  see  where  we  have  now  got  to  in  the  scale  of  size.  The 
following  comparative  table  of  distances  will  help  to  show  us  where  we 


Distance  of  the  sun 150,000,000 

Limit  of  the  solar  system  (Orbit  of  Pluto) ....  5,800,000,000 

Distance  of  the   nearest  star   40,000,000,000,000 

Distance  of  nearest  external  galaxy 8,000,000,000,000,000,000 

Distance  of  furthest  galaxy  yet  observed ....     3,000,000,000,000,000,000,000 

Some  people  complain  that  they  cannot  realize  these  figures.  Of  course 
they  cannot.  But  that  is  the  last  thing  one  wants  to  do  with  big  numbers — 
to  "realize"  them.  In  a  few  weeks  time  our  finance  minister  in  England 
will  be  presenting  his  annual  budget  of  about  ^900,000,000.  Do  you  sup- 
pose that  by  way  of  preparation,  he  throws  himself  into  a  state  of  trance  in 
which  he  can  visualize  the  vast  pile  of  coins  or  notes  or  commodities 
that  it  represents?  I  am  quite  sure  he  cannot  "realize"  ^900,000,000.  But 
he  can  spend  it.  It  is  a  fallacious  idea  that  these  big  numbers  create  a 
difficulty  in  comprehending  astronomy;  they  can  only  do  so  if  you  are 
seeking  the  wrong  sort  of  comprehension.  They  are  not  meant  to  be 
gaped  at,  but  to  be  manipulated  and  used.  It  is  as  easy  to  use  millions 


and  billions  and  trillions  for  our  counters  as  ones  and  twos  and  threes. 
What  I  want  to  call  attention  to  in  the  above  table  is  that  since  we  are 
going  out  beyond  the  Milky  Way  we  have  taken  a  very  big  step  up  in 
the  scale  of  distance. 

The  remarkable  thing  that  has  been  discovered  about  these  galaxies 
is  that  (except  three  or  four  of  the  nearest  of  them)  they  are  running 
away  from  our  own  galaxy;  and  the  further  they  are  away,  the  faster  they 
go.  The  distant  ones  have  very  high  speeds.  On  the  average  the  speed 
is  proportional  to  the  distance,  so  that  a  galaxy  10  million  light-years 
away  recedes  at  1500  kilometres  per  second,  one  50  million  light-years 
away  recedes  at  7500  kilometres  per  second,  and  so  on.  The  fastest  yet 
discovered  recedes  at  42,000  kilometres  per  second. 

Why  are  they  all  running  away  from  us  ?  If  we  think  a  little,  we  shall 
see  that  the  aversion  is  not  especially  directed  against  us;  they  are  running 
away  from  us,  but  they  are  also  running  away  from  each  other.  If  this 
room  were  to  expand  10  per  cent  in  its  dimensions,  the  seats  all  separating 
in  proportion,  you  would  at  first  think  that  everyone  was  moving  away 
from  you;  the  man  10  metres  away  has  moved  i  metre  further  off;  the 
man  20  metres  away  has  moved  2  metres  further  off;  and  so  on.  Just 
as  with  the  galaxies,  the  recession  is  proportional  to  the  distance.  This 
law  of  proportion  is  characteristic  of  a  uniform  expansion,  not  directed 
away  from  any  one  centre,  but  causing  a  general  scattering  apart.  So  we 
conclude  that  recession  of  the  nebulae  is  an  eflect  of  uniform  expansion. 

The  system  of  the  galaxies  is  all  the  universe  we  know,  and  indeed 
we  have  strong  reason  to  believe  that  it  is  the  whole  physical  universe. 
The  expansion  of  the  system,  or  scattering  apart  of  the  galaxies,  is  there- 
fore commonly  referred  to  as  the  expansion  of  the  universe;  and  the 
problem  which  it  raises  is  the  problem  of  the  "expanding  universe." 

The  expansion  is  proceeding  so  fast  that,  at  the  present  rate,  the  nebulae 
will  recede  to  double  their  present  distances  in  1300  million  years.  Astron- 
omers will  have  to  double  the  apertures  of  their  telescopes  every  1300 
million  years  in  order  to  keep  pace  with  the  recession.  But  seriously  1300 
million  years  is  not  a  long  period  of  cosmic  history;  I  have  already  men- 
tioned it  as  the  age  of  terrestrial  rocks.  It  comes  as  a  surprise  that  the 
universe  should  have  doubled  its  dimensions  within  geological  times. 
It  means  that  we  cannot  go  back  indefinitely  in  time;  and  indeed  the 
enormous  time-scale  of  billions  [The  English  "billion"  is  equivalent  to 
the  American  "trillion."]  of  years,  which  was  fashionable  ten  years  ago, 
must  be  drastically  cut  down.  We  are  becoming  reconciled  to  this  speed- 
ing up  of  the  time-scale  of  evolution,  for  various  other  lines  of  evidence 
have  convinced  us  that  it  is  essential.  It  seems  clear  now  that  we  must 


take  an  upper  limit  to  the  age  of  the  stars  not  greater  than  10,000  million 
years;  previously,  an  age  of  a  thousand  times  longer  was  commonly 

For  reasons  which  I  cannot  discuss  fully  we  believe  that  along  with 
the  expansion  of  the  material  universe  there  is  an  expansion  of  space 
itself.  The  idea  is  that  the  island  galaxies  are  scattered  throughout  a 
"spherical  space."  Spherical  space  means  that  if  you  keep  going  straight 
on  in  any  direction  you  will  ultimately  find  yourself  back  at  your  starting 
point.  This  is  analogous  to  what  happens  when  you  travel  straight  ahead 
on  the  earth;  you  reach  your  starting  point  again,  having  gone  round  the 
world.  But  here  we  apply  the  analogy  to  an  extra  dimension — to  space 
instead  of  to  a  surface.  I  realize,  of  course,  that  this  conception  of  a 
closed  spherical  space  is  very  difficult  to  grasp,  but  really  it  is  not  worse 
than  the  older  conception  of  infinite  open  space  which  no  one  can  properly 
imagine.  No  one  can  conceive  infinity;  one  just  uses  the  term  by  habit 
without  trying  to  grasp  it.  If  I  may  refer  to  our  English  expression,  "out 
of  the  frying-pan  into  the  fire,"  I  suggest  that  if  you  feel  that  in  receiving 
this  modern  conception  of  space  you  are  falling  into  the  fire,  please 
remember  that  you  are  at  least  escaping  from  the  frying-pan. 

Spherical  space  has  many  curious  properties.  I  said  that  if  you  go 
straight  ahead  in  any  direction  you  will  return  to  your  starting  point.  So 
if  you  look  far  enough  in  any  direction  and  there  is  nothing  in  the  way, 
you  ought  to  see — the  back  of  your  head.  Well,  not  exactly — because 
light  takes  at  least  6000  million  years  to  travel  round  the  universe  and 
your  head  was  not  there  when  it  started.  But  you  will  understand  the 
general  idea.  However,  these  curiosities  do  not  concern  us  much.  The 
main  point  is  that  if  the  galaxies  are  distributed  over  the  spherical  space 
more  or  less  in  the  same  way  that  human  beings  are  distributed  over  the 
earth,  they  cannot  form  an  expanding  system — they  cannot  all  be  receding 
from  one  another — unless  the  space  itself  expands.  So  the  expansion  of 
the  material  system  involves,  and  is  an  aspect  of,  an  expansion  of  space. 

This  scattering  apart  of  the  galaxies  was  not  unforeseen.  As  far  back 
as  1917,  Professor  W.  de  Sitter  showed  that  there  was  reason  to  expect 
this  phenomenon  and  urged  astronomers  to  look  for  it.  But  it  is  only 
recently  that  radial  velocities  of  spiral  nebulae  have  been  measured  in 
sufficient  numbers  to  show  conclusively  that  the  scattering  occurs.  It  is 
one  of  the  deductions  from  relativity  theory  that  there  must  exist  a  force, 
known  as  "cosmical  repulsion,"  which  tends  to  produce  this  kind  of 
scattering  in  which  every  object  recedes  from  every  other  object.  You 
know  the  theory  of  relativity  led  to  certain  astronomical  consequences 
— a  bending  of  light  near  the  sun  detectable  at  eclipses,  a  motion  of  the 


perihelion  of  Mercury,  a  red-shift  of  spectral  lines — which  have  been 
more  or  less  satisfactorily  verified.  The  existence  of  cosmical  repulsion 
is  an  equally  definite  consequence  of  the  theory,  though  this  is  not  so 
widely  known — partly  because  it  comes  from  a  more  difficult  branch  of 
the  theory  and  was  not  noticed  so  early,  and  perhaps  partly  because  it  is 
not  so  directly  associated  with  the  magic  name  of  Einstein. 

I  can  see  no  reason  to  doubt  that  the  observed  recession  of  the  spiral 
nebulae  is  due  to  cosmical  repulsion,  and  is  the  effect  predicted  by 
relativity  theory  which  we  were  hoping  to  find.  Many  other  explanations 
have  been  proposed — some  of  them  rather  fantastic — and  there  has  been 
a  great  deal  of  discussion  which  seems  to  me  rather  pointless.  In  this,  as 
in  other  developments  of  scientific  exploration,  we  must  recognize  the 
limitations  of  our  present  knowledge  and  be  prepared  to  consider  revolu- 
tionary changes.  But  when,  as  in  this  case,  observation  agrees  with  what 
our  existing  knowledge  had  led  us  to  expect,  it  is  reasonable  to  feel 
encouraged  to  pursue  the  line  of  thought  which  has  proved  successful; 
and  there  seems  little  excuse  for  an  outburst  of  unsupported  speculation. 

.  ,  ,  Now  we  have  been  all  over  the  universe.  If  my  survey  has  been 
rather  inadequate,  I  might  plead  that  light  takes  6000  million  years  to 
make  the  circuit  that  I  have  made  in  an  hour.  Or  rather,  that  was  the 
original  length  of  the  circuit;  but  the  universe  is  expanding  continually, 
and  whilst  I  have  been  talking  the  increase  of  the  circuit  amounts  to  one 
or  two  more  days'  journey  for  the  light.  Anyhow,  the  time  has  come  to 
leave  this  nightmare  of  immensity  and  find  again,  among  the  myriads 
of  orbs,  the  tiny  planet  which  is  our  home. 



A  Young  Man  Looking  at  Rocks 



From  The  Old  Red  Sandstone 

bettering  their  circumstances,  and  adding  to  the  amount  of  their 
enjoyment,  is  a  very  simple  one.  Do  not  seek  happiness  in  what  is  mis- 
named pleasure;  seek  it  rather  in  what  is  termed  study.  Keep  your  con- 
sciences clear,  your  curiosity  fresh,  and  embrace  every  opportunity  of 
cultivating  your  minds.  You  will  gain  nothing  by  attending  Chartist 
meetings.  The  fellows  who  speak  nonsense  with  fluency  at  these  assem- 
blies, and  deem  their  nonsense  eloquence,  are  totally  unable  to  help  either 
you  or  themselves :  or,  if  they  do  succeed  in  helping  themselves,  it  will  be 
all  at  your  expense.  Leave  them  to  harangue  unheeded,  and  set  yourselves 
to  occupy  your  leisure  hours  in  making  yourselves  wiser  men.  Learn  to 
make  a  right  use  of  your  eyes;  the  commonest  things  are  worth  looking 
at — even  stones  and  weeds,  and  the  most  familiar  animals. 

It  was  twenty  years  last  February  since  I  set  out,  a  little  before  sunrise 
to  make  my  first  acquaintance  with  a  life  of  labour  and  restraint:  and  I 
have  rarely  had  a  heavier  heart  than  on  that  morning.  I  was  but  a  slim, 
loose-jointed  boy  at  the  time,  fond  of  the  pretty  intangibilities  of  romance, 
and  of  dreaming  when  broad  awake;  and,  woeful  change!  I  was  now 
going  to  work  at  what  Burns  has  instanced,  in  his  "Twa  Dogs"  as  one  of 
the  most  disagreeable  of  all  employments, — to  work  in  a  quarry.  Bating 
the  passing  uneasiness  occasioned  by  a  few  gloomy  anticipations,  the 
portion  of  my  life  which  had  already  gone  by  had  been  happy  beyond  the 
common  lot.  I  had  been  a  wanderer  among  rocks  and  woods,  a  reader  of 
curious  books  when  I  could  get  them,  a  gleaner  of  old  traditionary  stories: 
and  now  I  was  going  to  exchange  all  my  day-dreams,  and  all  my  amuse- 



ments,  for  the  kind  of  life  in  which  men  toil  every  day  that  they  may  be 
enabled  to  eat,  and  eat  every  day  that  they  may  be  enabled  to  toil! 

The  quarry  in  which  I  wrought  lay  on  the  southern  shore  of  a  noble 
inland  bay,  or  frith  rather,  with  a  little  clear  stream  on  the  one  side, 
and  a  thick  fir  wood  on  the  other.  It  had  been  opened  in  the  Old  Red 
Sandstone  of  the  district,  and  was  overtopped  by  a  huge  bank  of  diluvial 
clay,  which  rose  over  it  in  some  places  to  the  height  of  nearly  thirty  feet, 
and  which  at  this  time  was  rent  and  shivered,  wherever  it  presented  an 
open  front  to  the  weather,  by  a  recent  frost.  A  heap  of  loose  fragments, 
which  had  fallen  from  above,  blocked  up  the  face  of  the  quarry,  and  my 
first  employment  was  to  clear  them  away.  The  friction  of  the  shovel 
soon  blistered  my  hands,  but  the  pain  was  by  no  means  very  severe,  and  I 
wrought  hard  and  willingly,  that  I  might  see  how  the  huge  strata  below, 
which  presented  so  firm  and  unbroken  a  frontage,  were  to  be  torn  up 
and  removed.  Picks,  and  wedges,  and  levers,  were  applied  by  my 
brother- workers;  and,  simple  and  rude  as  I  had  been  accustomed  to  regard 
these  implements,  I  found  I  had  much  to  learn  in  the  way  of  using  them. 
They  all  proved  inefficient,  however,  and  the  workmen  had  to  bore  into 
one  of  the  inferior  strata,  and  employ  gunpowder.  The  process  was  new 
to  me,  and  I  deemed  it  a  highly  amusing  one;  it  had  the  merit,  too,  of 
being  attended  with  some  such  degree  of  danger  as  a  boating  or  rock  excur- 
sion, and  had  thus  an  interest  independent  of  its  novelty.  We  had  a  few 
capital  shots:  the  fragments  flew  in  every  direction;  and  an  immense 
mass  of  the  diluvium  came  toppling  down,  bearing  with  it  two  dead  birds, 
that  in  a  recent  storm  had  crept  into  one  of  the  deeper  fissures,  to  die  in 
the  shelter.  I  felt  a  new  interest  in  examining  them.  The  one  "was  a  pretty 
cock  goldfinch,  with  its  hood  of  vermilion,  and  its  wings  inlaid  with  the 
gold  to  which  it  owes  its  name,  as  unsoiled  and  smooth  as  if  it  had  been 
preserved  for  a  museum.  The  other,  a  somewhat  rarer  bird,  of  the  wood- 
pecker tribe,  was  variegated  with  light  blue  and  a  grayish  yellow.  I  was 
engaged  in  admiring  the  poor  little  things,  more  disposed  to  be  senti- 
mental, perhaps,  than  if  I  had  been  ten  years  older,  and  thinking  of  the 
contrast  between  the  warmth  and  jollity  of  their  green  summer  haunts, 
and  the  cold  and  darkness  of  their  last  retreat,  when  I  heard  our  employer 
bidding  the  workmen  lay  by  their  tools.  I  looked  up,  and  saw  the  sun 
sinking  behind  the  thick  fir  wood  beside  us,  and  the  long  dark  shadows  of 
the  trees  stretching  downwards  towards  the  shore. 

This  was  no  very  formidable  beginning  of  the  course  of  life  I  had  so 
much  dreaded.  To  be  sure,  my  hanas  were  a  little  sore,  and  I  felt  nearly 
as  much  fatigued  as  if  I  had  been  climbing  among  the  rocks;  but  I  had 
wrought  and  been  useful,  and  had  yet  enjoyed  the  day  fully  as  much  as 
usual.  It  was  no  small  matter,  too,  that  the  evening,  converted,  by  a  rare 


transmutation,  into  the  delicious  "blink  of  rest"  which  Burns  so  truthfully 
describes,  was  all  my  own.  I  was  as  light  of  heart  next  morning  as  any  of 
my  brother-workmen.  There  had  been  a  smart  frost  during  the  night,  and 
the  rime  lay  white  on  the  grass  as  we  passed  onwards  through  the  fields; 
but  the  sun  rose  in  a  clear  atmosphere,  and  the  day  mellowed,  as  it 
advanced,  into  one  of  those  delightful  days  of  early  spring  which  give  so 
pleasing  an  earnest  of  whatever  is  mild  and  genial  in  the  better  half  of  the 

The  gunpowder  had  loosened  a  large  mass  in  one  of  the  interior  strata, 
and  our  first  employment,  on  resuming  our  labours,  was  to  raise  it  from 
its  bed.  I  assisted  the  other  workmen  in  placing  it  on  edge,  and  was  much 
struck  by  the  appearance  of  the  platform  on  which  it  had  rested.  The 
entire  surface  was  ridged  and  furrowed  like  a  bank  of  sand  that  had  been 
left  by  the  tide  an  hour  before.  I  could  trace  every  bend  and  curvature, 
every  cross  hollow  and  counter  ridge,  of  the  corresponding  phenomena; 
for  the  resemblance  was  no  half  resemblance, — it  was  the  thing  itself; 
and  I  had  observed  it  a  hundred  and  a  hundred  times,  when  sailing  my 
little  schooner  in  the  shallows  left  by  the  ebb.  But  what  had  become  of  the 
waves  that  had  thus  fretted  the  solid  rock,  or  of  what  element  had  they 
been  composed  ?  I  felt  as  completely  at  fault  as  Robinson  Crusoe  did  on  his 
discovering  the  print  of  the  man's  foot  on  the  sand.  The  evening  furnished 
me  with  still  further  cause  of  wonder.  We  raised  another  block  in  a 
different  part  of  the  quarry,  and  found  that  the  area  of  a  circular  depres- 
sion in  the  stratum  below  was  broken  and  flawed  in  every  direction,  as 
if  it  had  been  the  bottom  of  a  pool  recently  dried  up,  which  had  shrunk 
and  split  in  the  hardening.  Several  large  stones  came  rolling  down  from 
the  diluvium  in  the  course  of  the  afternoon.  They  were  of  different 
qualities  from  the  sandstone  below,  and  from  one  another;  and,  what  was 
more  wonderful  still,  they  were  all  rounded  and  water-worn,  as  if  they  had 
been  tossed  about  in  the  sea  or  the  bed  of  a  river  for  hundreds  of  years. 
There  could  not,  surely,  be  a  more  conclusive  proof  that  the  bank  which 
had  enclosed  them  so  long  could  not  have  been  created  on  the  rock  on 
which  it  rested.  No  workman  ever  manufactures  a  half-worn  article,  and 
the  stones  were  all  half -worn!  And  if  not  the  bank,  why  then  the  sand- 
stone underneath?  I  was  lost  in  conjecture,  and  found  I  had  food  enough 
for  thought  that  evening,  without  once  thinking  of  the  unhappiness  of  a 
life  of  labour. 

The  immense  masses  of  diluvium  which  we  had  to  clear  away  rendered 
the  working  of  the  quarry  laborious  and  expensive,  and  all  the  party 
quitted  it  in  a  few  days,  to  make  trial  of  another  that  seemed  to  promise 
better.  The  one  we  left  is  situated,  as  I  have  said,  on  the  southern  shore 
of  an  inland  bay, — the  Bay  of  Cromarty;  the  one  to  which  we  removed 

100  THE  EARTH 

has  been  opened  in  a  lofty  wall  of  cliffs  that  overhangs  the  northern 
shore  of  the  Moray  Frith.  I  soon  found  I  was  to  be  no  loser  by  the  change. 
Not  the  united  labours  of  a  thousand  men  for  more  than  a  thousand  years 
could  have  furnished  a  better  section  of  the  geology  of  the  district  than  this 
range  of  cliffs.  It  may  be  regarded  as  a  sort  of  chance  dissection  on  the 
earth's  crust.  We  see  in  one  place  the  primary  rock,  with  its  veins  of 
granite  and  quartz,  its  dizzy  precipices  of  gneiss,  and  its  huge  masses 
o£  horneblend;  we  find  the  secondary  rock  in  another,  with  its  beds  of 
sandstone  and  shale,  its  spars,  its  clays,  and  its  nodular  limestones.  We 
discover  the  still  little-known  but  highly  interesting  fossils  of  the  Old 
Red  Sandstone  in  one  deposition;  we  find  the  beautifully  preserved  shells 
and  lignites  of  the  Lias  in  another.  There  are  the  remains  of  two  several 
creations  at  once  before  us.  The  shore,  too,  is  heaped  with  rolled  fragments 
of  almost  every  variety  of  rock, — basalts,  ironstones,  hyperstenes,  porphy- 
ries, bituminous  shales,  and  micaceous  schists.  In  short,  the  young  geologist, 
had  he  all  Europe  before  him  could  hardly  choose  for  himself  a  better 
field.  I  had,  however,  no  one  to  tell  me  so  at  the  time,  for  Geology  had 
not  yet  travelled  so  far  north;  and  so,  without  guide  or  vocabulary,  I  had 
to  grope  my  way  as  I  best  might,  and  find  out  all  its  wonders  for  myself. 
But  so  slow  was  the  process,  and  so  much  was  I  a  seeker  in  the  dark,  that 
the  facts  contained  in  these  few  sentences  were  the  patient  gatherings  of 

In  the  course  of  the  first  day's  employment  I  picked  up  a  nodular  mass 
of  blue  limestone,  and  laid  it  open  by  a  stroke  of  the  hammer.  Wonder- 
ful to  relate,  it  contained  inside  a  beautifully  finished  piece  of  sculpture,— 
one  of  the  volutes,  apparently,  of  an  Ionic  capital;  and  not  the  far-famed 
walnut  of  the  fairy  tale,  had  I  broken  the  shell  and  found  the  little  dog 
lying  within,  could  have  surprised  me  more.  Was  there  another  such 
curiosity  in  the  whole  world  ?  I  broke  open  a  few  other  nodules  of  similar 
appearance, — for  they  lay  pretty  thickly  on  the  shore, — and  found  that 
there  might  be.  In  one  of  these  there  were  what  seemed  to  be  the  scales 
of  fishes,  and  the  impressions  of  a  few  minute  bivalves,  prettily  striated; 
in  the  centre  of  another  there  was  actually  a  piece  of  decayed  wood.  Of 
all  Nature's  riddles,  these  seemed  to  me  to  be  at  once  the  most  interesting 
and  the  most  difficult  to  expound.  I  treasured  them  carefully  up,  and  was 
told  by  one  of  the  workmen  to  whom  I  showed  them,  that  there  was  a 
part  of  the  shore  about  two  miles  farther  to  the  west  where  curiously- 
shaped  stones,  somewhat  like  the  heads  of  boarding-pikes,  were  occasion- 
ally picked  up;  and  that  in  his  father's  days  the  country  people  called 
them  thunderbolts,  and  deemed  them  of  sovereign  efficacy  in  curing 
bewitched  cattle.  Our  employer,  on  quitting  the  quarry  for  the  building  or* 


which  we  were  to  be  engaged,  gave  all  the  workmen  a  half-holiday-  I 
employed  it  in  visiting  the  place  where  the  thunderbolts  had  fallen  so 
thickly,  and  found  it  a  richer  scene  of  wonder  than  I  could  have  fancied 
in  even  my  dreams. 

What  first  attracted  my  notice  was  a  detached  group  of  low-lying 
skerries,  wholly  different  in  form  and  colour  from  the  sandstone  cliffs 
above  or  the  primary  rocks  a  little  farther  to  the  west.  I  found  them  com- 
posed of  thin  strata  of  limestone,  alternating  with  thicker  beds  of  a  black 
slaty  substance,  which,  as  I  ascertained  in  the  course  of  the  evening,  burns 
with  a  powerful  flame,  and  emits  a  strong  bituminous  odour.  The  layers 
into  which  the  beds  readily  separate  are  hardly  an  eighth  part  of  an  inch 
in  thickness,  and  yet  on  every  layer  there  are  the  impressions  of  thousands 
and  tens  of  thousands  of  the  various  fossils  peculiar  to  the  Lias.  We  may 
turn  over  these  wonderful  leaves  one  after  one,  like  the  leaves  of  a 
herbarium,  and  find  the  pictorial  records  of  a  former  creation  in  every 
page:  scallops,  and  gryphites,  and  ammonites,  of  almost  every  variety 
peculiar  to  the  formation,  and  at  least  some  eight  of  ten  varieties  of 
belemnite;  twigs  of  wood,  leaves  of  plants,  cones  of  an  extinct  species  of 
pine,  bits  of  charcoal,  and  the  scales  of  fishes;  and,  as  if  to  render  their 
pictorial  appearance  more  striking,  though  the  leaves  of  this  interesting 
volume  are  of  a  deep  black,  most  of  the  impressions  are  of  a  chalky  white- 
ness. I  was  lost  in  admiration  and  astonishment,  and  found  my  very 
imagination  paralysed  by  an  assemblage  of  wonders  that  seemed  to  out- 
rival in  the  fantastic  and  the  extravagant  even  its  wildest  conceptions.  I 
passed  on  from  ledge  to  ledge,  like  the  traveller  of  the  tale  through  the 
city  of  statues,  and  at  length  found  one  of  the  supposed  aerolites  I  had 
come  in  quest  of  firmly  imbedded  in  a  mass  of  shale.  But  I  had  skill 
enough  to  determine  that  it  was  other  than  what  it  had  been  deemed. 
A  very  near  relative,  who  had  been  a  sailor  in  his  time  on  almost  every 
ocean,  and  had  visited  almost  every  quarter  of  the  globe,  had  brought 
home  one  of  these  meteoric  stones  with  him  from  the  coast  of  Java.  It 
was  of  a  cylindrical  shape  and  vitreous  texture,  and  it  seemed  to  have 
parted  in  the  middle  when  in  a  half-molten  state,  and  to  have  united 
again,  somewhat  awry,  ere  it  had  cooled  enough  to  have  lost  the  adhesive 
quality.  But  there  was  nothing  organic  in  its  structure;  whereas  the  stone 
I  had  now  found  was  organized  very  curiously  indeed.  It  was  of  a  coni- 
cal form  and  filamentary  texture,  the  filaments  radiating  in  straight  lines 
from  the  centre  to  the  circumference.  Finely-marked  veins  like  white 
threads  ran  transversely  through  these  in  its  upper  half  to  the  point;  while 
the  space  below  was  occupied  by  an  internal  cone,  formed  of  plates  that 
lay  parallel  to  the  base,  and  which,  like  watch-glasses,  were  concave  on  the 

102  THE  EARTH 

under  side  and  convex  on  the  upper.  I  learned  in  time  to  call  this  stone 
a  belemnite,  and  became  acquainted  with  enough  of  its  history  to  know 
that  it  once  formed  part  of  a  variety  of  cuttle-fish,  long  since  extinct. 

My  first  year  of  labour  came  to  a  close,  and  I  found  that  the  amount 
of  my  happiness  had  not  been  less  than  in  the  last  of  my  boyhood.  My 
knowledge,  too,  had  increased  in  more  than  the  skill  of  at  least  the  com- 
mon mechanic,  I  had  fitted  myself  for  independence.  The  additional 
experience  of  twenty  years  has  not  shown  me  that  there  is  any  necessary 
connection  between  a  life  of  toil  and  a  life  of  wretchedness;  and  when  I 
have  found  good  men  anticipating  a  better  and  a  happier  time  than 
either  the  present  or  the  past,  the  conviction  that  in  every  period  of  the 
world's  history  the  great  bulk  of  mankind  must  pass  their  days  in  labour, 
has  not  in  the  least  inclined  me  to  scepticism.  .  .  . 

One  important  truth  I  would  fain  press  on  the  attention  of  my  low- 
lier readers:  there  are  few  professions,  however  humble,  that  do  not  pre- 
sent their  peculiar  advantages  of  observation;  there  are  none,  I  repeat, 
in  which  the  exercise  of  the  faculties  does  not  lead  to  enjoyment.  I 
advise  the  stone-mason,  for  instance,  to  acquaint  himself  with  Geology. 
Much  of  his  time  must  be  spent  amid  the  rocks  and  quarries  of  widely- 
separated  localities.  The  bridge  or  harbour  is  no  sooner  completed  in  one 
district  than  he  has  to  remove  to  where  the  gentleman's  seat  or  farm- 
steading  is  to  be  erected  in  another;  and  so,  in  the  course  of  a  few  years, 
he  may  pass  over  the  whole  geological  scale,  even  when  restricted  to  Scot- 
land, from  the  Grauwacke  of  the  Lammermuirs,  to  the  Wealden  of 
Moray  or  the  Chalk-flints  of  Banffshire  and  Aberdeen;  and  this,  too, 
with  opportunities  of  observation  at  every  stage  which  can  be  shared  with 
him  by  only  the  gentleman  of  fortune  who  devotes  his  whole  time  to  the 
study.  Nay,  in  some  respects  his  advantages  are  superior  to  those  of  the 
amateur  himself.  The  latter  must  often  pronounce  a  formation  unfossilif- 
erous  when,  after  the  examination  of  at  most  a  few  days,  he  discovers  ir 
it  nothing  organic;  and  it  will  be  found  that  half  the  mistakes  of  geolo- 
gists have  arisen  from  conclusions  thus  hastily  formed.  But  the  working 
man,  whose  employments  have  to  be  carried  on  in  the  same  formation  for 
months,  perhaps  years,  together,  enjoys  better  opportunities  for  arriving 
at  just  decisions.  There  are,  besides,  a  thousand  varieties  of  accident  which 
lead  to  discovery, — floods,  storms,  landslips,  tides  of  unusual  height,  ebbs 
of  extraordinary  fall;  and  the  man  who  plies  his  labour  at  all  seasons  in 
the  open  air  has  by  much  the  best  chance  of  profiting  by  these.  There 
are  formations  which  yield  their  organisms  slowly  to  the  discoverer,  and 
the  proofs  which  establish  their  place  in  the  geological  scale  more  tardily 
.still.  I  was  acquainted  with  the  Old  Red  Sandstone  of  Ross  and  Cromarty 


for  nearly  ten  years  ere  I  had  ascertained  that  it  is  richly  fossiliferous, — 
a  discovery  which,  in  exploring  this  formation  in  those  localities,  some  of 
our  first  geologists  had  failed  to  anticipate:  I  was  acquainted  with  it  for 
nearly  ten  years  more  ere  I  could  assign  to  its  fossils  their  exact  place  in 
the  scale. 

. . .  Should  the  working  man  be  encouraged  by  my  modicum  of  success 
to  improve  his  opportunities  of  observation,  I  shall  have  accomplished  the 
whole  of  it.  It  cannot  be  too  extensively  known,  that  nature  is  vast  and 
knowledge  limited,  and  that  no  individual,  however  humble  in  place 
or  acquirement,  need  despair  of  adding  to  the  general  fund. 


Geological  Change 


[James  Hutton,  1726-1797]  and  his  school  that  this  globe  has  not 
always  worn  the  aspect  which  it  bears  at  present;  that  on  the  contrary, 
proofs  may  everywhere  be  culled  that  the  land  which  we  now  see  has 
been  formed  out  of  the  wreck  of  an  older  land.  Among  these  proofs,  the 
most  obvious  are  supplied  by  some  of  the  more'  familiar  kinds  of  rocks, 
which  teach  us  that,  though  they  are  now  portions  of  the  dry  land,  they 
were  originally  sheets  of  gravel,  sand,  and  mud,  which  had  been  worn 
from  the  face  of  long-vanished  continents,  and  after  being  spread  out 
over  the  floor  of  the  sea  were  consolidated  into  compact  stone,  and 
were  finally  broken  up  and  raised  once  more  to  form  part  of  the  dry 
land.  This  cycle  of  change  involved  two  great  systems  of  natural  proc- 
esses. On  the  one  hand,  men  were  taught  that  by  the  action  of  running 
water  the  materials  of  the  solid  land  are  in  a  state  of  continual  decay  and 
transport  to  the  ocean.  On  the  other  hand,  the  ocean  floor  is  liable  from 
time  to  time  to  be  upheaved  by  some  stupendous  internal  force  akin 

104  THE  EARTH 

to  that  which  gives  rise  to  the  volcano  and  the  earthquake.  Hutton 
further  perceived  that  not  only  had  the  consolidated  materials  been  dis- 
rupted and  elevated,  but  that  masses  of  molten  rock  had  been  thrust 
upward  among  them,  and  had  cooled  and  crystallized  in  large  bodies 
of  granite  and  other  eruptive  rocks  which  form  so  prominent  a  feature 
on  the  earth's  surface. 

It  was  a  special  characteristic  of  this  philosophical  system  that  it  sought 
in  the  changes  now  in  progress  on  the  earth's  surface  an  explanation  of 
those  which  occurred  in  older  times.  Its  founder  refused  to  invent  causes 
or  modes  of  operation,  for  those  with  which  he  was  familiar  seemed  to 
him  adequate  to  solve  the  problems  with  which  he  attempted  to  deal. 
Nowhere  was  the  profoundness  of  his  insight  more  astonishing  than  in 
the  clear,  definite  way  in  which  he  proclaimed  and  reiterated  his  doc- 
trine, that  every  part  of  the  surface  of  the  continents,  from  mountain 
top  to  seashore,  is  continually  undergoing  decay,  and  is  thus  slowly 
travelling  to  the  sea.  He  saw  that  no  sooner  will  the  sea  floor  be  elevated 
into  new  land  than  it  must  necessarily  become  a  prey  to  this  universal 
and  unceasing  degradation.  He  perceived  that  as  the  transport  of  dis- 
integrated material  is  carried  on  chiefly  by  running  water,  rivers  must 
slowly  dig  out  for  themselves  the  channels  in  which  they  flow,  and  thus 
that  a  system  of  valleys,  radiating  from  the  water  parting  of  a  country, 
must  necessarily  result  from  the  descent  of  the  streams  from  the  moun- 
tain crests  to  the  sea.  He  discerned  that  this  ceaseless  and  wide-spread 
decay  would  eventually  lead  to  the  entire  demolition  of  the  dry  land,  but 
he  contended  that  from  time  to  time  this  catastrophe  is  prevented  by  the 
operation  of  the  under-ground  forces,  whereby  new  continents  are  up- 
heaved from  the  bed  of  the  ocean.  And  thus  in  his  system  a  due 
proportion  is  maintained  between  land  and  water,  and  the  condition  of 
the  earth  as  a  habitable  globe  is  preserved. 

A  theory  of  the  earth  so  simple  in  outline,  so  bold  in  conception,  so 
full  of  suggestion,  and  resting  on  so  broad  a  base  of  observation  and 
reflection,  ought  (we  think)  to  have  commanded  at  once  the  attention 
of  men  of  science,  even  if  it  did  not  immediately  awaken  the  interest 
of  the  outside  world;  but,  as  Playfair  sorrowfully  admitted,  it  attracted 
notice  only  very  slowly,  and  several  years  elapsed  before  any  one  showed 
himself  publicly  concerned  about  it,  either  as  an  enemy  or  a  friend. 
Some  of  its  earliest  critics  assailed  it  for  what  they  asserted  to  be  its 
irreligious  tendency, — an  accusation  which  Hutton  repudiated  with  much 
warmth.  The  sneer  levelled  by  Cowper  a  few  years  earlier  at  all  inquiries 
into  the  history  of  the  universe  was  perfectly  natural  and  intelligible  from 
that  poer's  point  of  view.  There  was  then  a  wide-spread  belief  that  this 


world  came  into  existence  some  six  thousand  years  ago,  and  that  any 
attempt  greatly  to  increase  that  antiquity  was  meant  as  a  blow  to  the 
authority  of  Holy  Writ.  So  far,  however,  from  aiming  at  the  overthrow 
o£  orthodox  beliefs,  Hutton  evidently  regarded  his  "Theory"  as  an 
important  contribution  in  aid  of  natural  religion.  He  dwelt  with 
unfeigned  pleasure  on  the  multitude  of  proofs  which  he  was  able  to 
accumulate  of  an  orderly  design  in  the  operations  of  Nature,  decay  and 
renovation  being  so  nicely  balanced  as  to  maintain  the  habitable  con- 
dition of  the  planet.  But  as  he  refused  to  admit  the  predominance  of 
violent  action  in  terrestrial  changes,  and  on  the  contrary  contended  for 
the  efficacy  of  the  quiet,  continuous  processes  which  we  can  even  now 
see  at  work  around  us,  he  was  constrained  to  require  an  unlimited 
duration  of  past  time  for  the  production  of  those  revolutions  of  which 
he  perceived  such  clear  and  abundant  proofs  in  the  crust  of  the  earth. 
The  general  public,  however,  failed  to  comprehend  that  the  doctrine  of 
the  high  antiquity  of  the  globe  was  not  inconsistent  with  the  com- 
paratively recent  appearance  of  man, — a  distinction  which  seems  so 
obvious  now. 

Hutton  died  in  1797,  beloved  and  regretted  by  the  circle  of  friends 
who  had  learned  to  appreciate  his  estimable  character  and  to  admire  his 
genius,  but  with  little  recognition  from  the  world  at  large.  Men  knew 
not  then  that  a  great  master  had  passed  away  from  their  midst,  who 
had  laid  broad  and  deep  the  foundations  of  a  new  science;  that  his  name 
would  become  a  household  word  in  after  generations,  and  that  pilgrims 
would  come  from  distant  lands  to  visit  the  scenes  from  which  he  drew 
his  inspiration.  .  .  . 

Clear  as  was  the  insight  and  sagacious  the  inferences  of  the  great 
masters  [of  the  Edinburgh  school]  in  regard  to  the  history  of  the  globe, 
their  vision  was  necessarily  limited  by  the  comparatively  narrow  range 
of  ascertained  fact  which  up  to  their  time  had  been  established.  They 
taught  men  to  recognize  that  the  present  world  is  built  of  the  ruins  of 
an  earlier  one,  and  they  explained  with  admirable  perspicacity  the  oper- 
ation of  the  processes  whereby  the  degradation  and  renovation  of  land 
are  brought  about.  But  they  never  dreamed  that  a  long  and  orderly  series 
of  such  successive  destructions  and  renewals  had  taken  place  and  had 
left  their  records  in  the  crust  of  the  earth.  They  never  imagined  that 
from  these  records  it  would  be  possible  to  establish  a  determinate 
chronology  that  could  be  read  everywhere  and  applied  to  the  elucidation 
of  the  remotest  quarter  of  the  globe.  It  was  by  the  memorable  observa- 
tions and  generalizations  of  William  Smith  that  this  vast  extension  of 
our  knowledge  of  the  past  history  of  the  earth  became  possible.  While 

106  THE  EARTH 

the  Scottish  philosophers  were  building  up  their  theory  here,  Smith  was 
quietly  ascertaining  by  extended  journeys  that  the  stratified  rocks  of  the 
west  of  England  occur  in  a  definite  sequence,  and  that  each  well-marked 
group  of  them  can  be  discriminated  from  the  others  and  identified  across 
the  country  by  means  of  its  inclosed  organic  remains.  It  is  nearly  a  hun- 
dred years  since  he  made  known  his  views,  so  that  by  a  curious  coin- 
cidence we  may  fitly  celebrate  on  this  occasion  the  centenary  of  William 
Smith  as  well  as  that  of  James  Hutton.  No  single  discovery  has  ever  had 
a  more  momentous  and  far-reaching  influence  on  the  progress  of  a 
science  than  that  law  of  organic  succession  which  Smith  established.  At 
first  it  served  merely  to  determine  the  order  of  the  stratified  rocks  of 
England.  But  it  soon  proved  to  possess  a  world-wide  value,  for  it  was 
found  to  furnish  the  key  to  the  structure  of  the  whole  stratified  crust 
of  the  earth.  It  showed  that  within  that  crust  lie  the  chronicles  of  a  long 
history  of  plant  and  animal  life  upon  this  planet,  it  supplied  the  means 
of  arranging  the  materials  for  this  history  in  true  chronological  sequence, 
and  it  thus  opened  out  a  magnificent  vista  through  a  vast  series  of  ages, 
each  marked  by  its  own  distinctive  types  of  organic  life,  which,  in  pro- 
portion to  their  antiquity,  departed  more  and  more  from  the  aspect  of  the 
living  world. 

Thus  a  hundred  years  ago,  by  the  brilliant  theory  of  Hutton  and  the 
fruitful  generalization  of  Smith,  the  study  of  the  earth  received  in  our 
country  the  impetus  which  has  given  birth  to  the  modern  science  of 
geology.  .  .  . 

From  the  earliest  times  the  natural  features  of  the  earth's  surface  have 
arrested  the  attention  of  mankind.  The  rugged  mountain,  the  cleft  ravine, 
the  scarped  cliff,  the  solitary  bowlder,  have  stimulated  curiosity  and 
prompted  many  a  speculation  as  to  their  origin.  The  shells  embedded  by 
millions  in  the  solid  rocks  of  hills  far  removed  from  the  seas  have  still 
further  pressed  home  these  "obstinate  questionings."  But  for  many  long 
centuries  the  advance  of  inquiry  into  such  matters  was  arrested  by  the 
paramount  influence  of  orthodox  theology.  It  was  not  merely  that  the 
church  opposed  itself  to  the  simple  and  obvious  interpretation  of  these 
natural  phenomena.  So  implicit  had  faith  become  in  the  accepted  views 
of  the  earth's  age  and  of  the  history  of  creation,  that  even  laymen  of 
intelligence  and  learning  set  themselves  unbidden  and  in  perfect  good 
faith  to  explain  away  the  difficulties  which  nature  so  persistently  raised 
up,  and  to  reconcile  her  teachings  with  those  of  the  theologians.  .  .  . 

It  is  the  special  glory  of  the  Edinburgh  school  of  geology  to  have  cast 
aside  all  this  fanciful  trifling.  Hutton  boldly  proclaimed  that  it  was  no 
part  of  his  philosophy  to  account  for  the  beginning  of  things.  His  con- 


cern  lay  only  with  the  evidence  furnished  by  the  earth  itself  as  to  its 
origin.  With  the  intuition  of  true  genius  he  early  perceived  that  the  only 
basis  from  which  to  explore  what  has  taken  place  in  bygone  time  is  a 
knowledge  of  what  is  taking  place  to-day.  He  thus  founded  his  system 
upon  a  careful  study  of  the  process  whereby  geological  changes  are  now 
brought  about.  .  .  . 

Fresh  life  was  now  breathed  into  the  study  of  the  earth.  A  new  spirit 
seemed  to  animate  the  advance  along  every  pathway  of  inquiry.  Facts 
that  had  long  been  familiar  came  to  possess  a  wider  and  deeper  meaning 
when  their  connection  with  each  other  was  recognized  as  parts  of  one 
great  harmonious  system  of  continuous  change.  In  no  department  of 
Nature,  for  example,  was  this  broader  vision  more  remarkably  displayed 
than  in  that  wherein  the  circulation  of  water  between  land  and  sea  plays 
the  most  conspicuous  part.  From  the  earliest  times  men  had  watched  the 
coming  of  clouds,  the  fall  of  rain,  the  flow  of  rivers,  and  had  recognized 
that  on  this  nicely  adjusted  machinery  the  beauty  and  fertility  of  the  land 
depend.  But  they  now  learned  that  this  beauty  and  fertility  involve  a 
continual  decay  of  the  terrestrial  surface;  that  the  soil  is  a  measure  of  this 
decay,  and  would  cease  to  afford  us  maintenance  were  it  not  continually 
removed  and  renewed,  that  through  the  ceaseless  transport  of  soil  by 
rivers  to  the  sea  the  face  of  the  land  is  slowly  lowered  in  level  and  carved 
into  mountain  and  valley,  and  that  the  materials  thus  borne  outwards  to 
the  floor  of  the  ocean  are  not  lost,  but  accumulate  there  to  form  rocks, 
which  in  the  end  will  be  upraised  into  new  lands.  Decay  and  renovation, 
in  well-balanced  proportions,  were  thus  shown  to  be  the  system  on  which 
the  existence  of  the  earth  as  a  habitable  globe  had  been  established.  It 
was  impossible  to  conceive  that  the  economy  of  the  planet  could  be  main- 
tained on  any  other  basis.  Without  the  circulation  of  water  the  life  of 
plants  and  animals  would  be  impossible,  and  with  the  circulation  the 
decay  of  the  surface  of  the;  land  and  the  renovation  of  its  disintegrated 
materials  are  necessarily  involved. 

As  it  is  now,  so  must  it  have  been  in  past  time.  Hutton  and  Playfair 
pointed  to  the  stratified  rocks  of  the  earth's  crust  as  demonstrations  that 
the  same  processes  which  are  at  work  to-day  have  been  in  operation  from 
a  remote  antiquity.  .  .  . 

Obviously,  however,  human  experience,  in  the  few  centuries  during 
which  attention  has  been  turned  to  such  subjects,  has  been  too  brief  to 
warrant  any  dogmatic  assumption  that  the  various  natural  processes 
must  have  been  carried  on  in  the  past  with  the  same  energy  and  at  the 
same  rate  as  they  are  carried  on  now.  ...  It  was  an  error  to  take  for 
granted  that  no  other  kind  of  process  or  influence,  nor  any  variation  in 

108  THE  EARTH 

the  rate  of  activity  save  those  of  which  man  has  had  actual  cognizance, 
has  played  a  part  in  the  terrestrial  economy.  The  uniformitarian  writers 
laid  themselves  open  to  the  charge  of  maintaining  a  kind  of  perpetual 
motion  in  the  machinery  of  Nature.  They  could  find  in  the  records  of  the 
earth's  history  no  evidence  of  a  beginning,  no  prospect  of  an  end.  .  .  . 

The  discoveries  of  William  Smith,  had  they  been  adequately  under- 
stood, would  have  been  seen  to  offer  a  corrective  to  this  rigidly  uni- 
formitarian conception,  for  they  revealed  that  the  crust  of  the  earth  con- 
tains the  long  record  of  an  unmistakable  order  of  progression  in  organic 
types.  They  proved  that  plants  and  animals  have  varied  widely  in  suc- 
cessive periods  of  the  earth's  history;  the  present  condition  of  organic 
life  being  only  the  latest  phase  of  a  long  preceding  series,  each  stage  of 
which  recedes  further  from  the  existing  aspect  of  things  as  we  trace  it 
backward  into  the  past.  And  though  no  relic  had  yet  been  found,  or 
indeed  was  ever  likely  to  be  found,  of  the  first  living  things  that  appeared 
upon  the  earth's  surface,  the  manifest  simplification  of  types  in  the 
older  formations  pointed  irresistibly  to  some  beginning  from  which  the 
long  procession  has  taken  its  start.  If  then  it  could  thus  be  demonstrated 
that  there  had  been  upon  the  globe  an  orderly  march  of  living  forms 
from  the  lowliest  grades  in  early  times  to  man  himself  to-day,  and  thus 
that  in  one  department  of  her  domain,  extending  through  the  greater 
portion  of  the  records  of  the  earth's  history,  Nature  had  not  been 
uniform,  but  had  followed  a  vast  and  noble  plan  of  evolution,  surely  it 
might  have  been  expected  that  those  who  discovered  and  made  known 
this  plan  would  seek  to  ascertain  whether  some  analogous  physical  pro- 
gression from  a  definite  beginning  might  not  be  discernible  in  the  frame- 
work of  the  globe  itself. 

But  the  early  masters  of  the  science  labored  under  two  great  disad- 
vantages. In  the  first  place,  they  found  the  oldest  records  of  the  earth's 
history  so  broken  up  and  effaced  as  to  be  no  longer  legible.  And  in  the 
second  place,  .  .  .  they  considered  themselves  bound  to  search  for  facts, 
not  to  build  up  theories;  and  as  in  the  crust  of  the  earth  they  could  find 
no  facts  which  threw  any  light  upon  the  primeval  constitution  and  sub- 
sequent development  of  our  planet,  they  shut  their  ears  to  any  theoretical 
interpretations  that  might  be  offered  from  other  departments  of  science. . . . 

What  the  more  extreme  members  of  the  uniformitarian  school  failed 
to  perceive  was  the  absence  of  all  evidence  that  terrestrial  catastrophes 
even  on  a  colossal  scale  might  not  be  a  part  of  the  present  economy  of 
this  globe.  Such  occurrences  might  never  seriously  affect  the  whole 
earth  at  one  time,  and  might  return  at  such  wide  intervals  that  no 
example  of  them  has  yet  been  chronicled  by  man.  But  that  they  have 


occurred  again  and  again,  and  even  within  comparatively  recent  geolog- 
ical times,  hardly  admits  of  serious  doubt.  .  .  . 

As  the  most  recent  and  best  known  of  these  great  transformations,  the 
Ice  Age  stands  out  conspicuously  before  us.  ...  There  can  not  be  any 
doubt  that  after  man  had  become  a  denizen  of  the  earth,  a  great  physical 
change  came  over  the  Northern  hemisphere.  The  climate,  which  had 
previously  been  so  mild  that  evergreen  trees  flourished  within  ten  or 
twelve  degrees  of  the  North  Pole,  now  became  so  severe  that  vast  sheets 
of  snow  and  ice  covered  the  north  of  Europe  and  crept  southward  beyond 
the  south  coast  of  Ireland,  almost  as  far  as  the  southern  shores  of 
England,  and  across  the  Baltic  into  France  and  Germany.  This  Arctic 
transformation  was  not  an  episode  that  lasted  merely  a  few  seasons,  and 
left  the  land  to  resume  thereafter  its  ancient  aspect.  With  various  suc- 
cessive fluctuations  it  must  have  endured  for  many  thousands  of  years. 
When  it  began  to  disappear  it  probably  faded  away  as  slowly  and 
imperceptibly  as  it  had  advanced,  and  when  it  finally  vanished  it  left 
Europe  and  North  America  profoundly  changed  in  the  character  alike 
of  their  scenery  and  of  their  inhabitants.  The  rugged  rocky  contours  of 
earlier  times  were  ground  smooth  and  polished  by  the  march  of  the  ice 
across  them,  while  the  lower  grounds  were  buried  under  wide  and  thick 
sheets  of  clay,  gravel,  and  sand,  left  behind  by  the  melting  ice.  The 
varied  and  abundant  flora  which  had  spread  so  far  within  the  Arctic 
circle  was  driven  away  into  more  southern  and  less  ungenial  climes. 
But  most  memorable  of  all  was  the  extirpation  of  the  prominent  large 
animals  which,  before  the  advent  of  the  ice,  had  roamed  over  Europe. 
The  lions,  hyenas,  wild  horses,  hippopotamuses,  and  other  creatures 
either  became  entirely  extinct  or  were  driven  into  the  Mediterranean 
basin  and  into  Africa.  In  their  place  came  northern  forms — the  reindeer, 
glutton,  musk  ox,  wooly  rhinoceros,  and  mammoth. 

Such  a  marvellous  transformation  in  climate,  in  scenery,  in  vegetation 
and  in  inhabitants,  within  what  was  after  all  but  a  brief  portion  of 
geological  time,  though  it  may  have  involved  no  sudden  or  violent  con- 
vulsion, is  surely  entitled  to  rank  as  a  catastrophe  in  the  history  of  the 
globe.  It  was  probably  brought  about  mainly  if  not  entirely  by  the  oper- 
ation of  forces  external  to  the  earth.  No  similar  calamity  having  befallen 
the  continents  within  the  time  during  which  man  has  been  recording  his 
experience,  the  Ice  Age  might  be  cited  as  a  contradiction  to  the  doc- 
trine of  uniformity.  And  yet  it  manifestly  arrived  as  part  of  the  estab- 
lished order  of  Nature.  Whether  or  not  we  grant  that  other  ice  ages 
preceded  the  last  great  one,  we  must  admit  that  the  conditions  under 
which  it  arose,  so  far  as  we  know  them,  might  conceivably  have  occurred 

110  THE  EARTH 

before  and  may  occur  again.  The  various  agencies  called  into  play  by  the 
extensive  refrigeration  of  the  Northern  hemisphere  were  not  different  from 
those  with  which  we  are  familiar.  Snow  fell  and  glaciers  crept  as  they 
do  to-day.  Ice  scored  and  polished  rocks  exactly  as  it  still  does  among 
the  Alps  and  in  Norway.  There  was  nothing  abnormal  in  the  phenomena, 
save  the  scale  on  which  they  were  manifested.  And  thus,  taking  a  broad 
view  of  the  whole  subject,  we  recognize  the  catastrophe,  while  at  the 
same  time  we  see  in  its  progress  the  operation  of  those  same  natural 
processes  which  we  know  to  be  integral  parts  of  the  machinery  whereby 
the  surface  of  the  earth  is  continually  transformed. 

Among  the  debts  which  science  owes  to  the  Huttonian  school,  not  the 
least  memorable  is  the  promulgation  of  the  first  well-founded  con- 
ceptions of  the  high  antiquity  of  the  globe.  Some  six  thousand  years  had 
previously  been  believed  to  comprise  the  whole  life  of  the  planet,  and 
indeed  of  the  entire  universe.  When  the  curtain  was  then  first  raised 
that  had  veiled  the  history  of  the  earth,  and  men,  looking  beyond  the 
brief  span  within  which  they  had  supposed  that  history  to  have  been 
transacted,  beheld  the  records  of  a  long  vista  of  ages  stretching  far  away 
into  a  dim  illimitable  past,  the  prospect  vividly  impressed  their  imagina- 
tion. Astronomy  had  made  known  the  immeasurable  fields  of  space;  the 
new  science  of  geology  seemed  now  to  reveal  boundless  distances  of 
time.  .  .  . 

The  universal  degradation  of  the  land,  so  notable  a  characteristic  of 
the  earth's  surface,  has  been  regarded  as  an  extremely  slow  process. 
Though  it  goes  on  without  ceasing,  yet  from  century  to  century  it  seems 
to  leave  hardly  any  perceptible  trace  on  the  landscapes  of  a  country. 
Mountains  and  plains,  hills  and  valleys  appear  to  wear  the  same  familiar 
aspect  which  is  indicated  in  the  oldest  pages  of  history.  This  obvious 
slowness  in  one  of  the  most  important  departments  of  geological  activity 
doubtless  contributed  in  large  measure  to  form  and  foster  a  vague  belief 
in  the  vastness  of  the  antiquity  required  for  the  evolution  of  the  earth. 

But,  as  geologists  eventually  came  to  perceive,  the  rate  of  degradation 
of  the  land  is  capable  of  actual  measurement.  The  amount  of  material 
worn  away  from  the  surface  of  any  drainage  basin  and  carried  in  the 
form  of  mud,  sand,  or  gravel,  by  the  main  river  into  the  sea  represents 
the  extent  to  which  that  surface  has  been  lowered  by  waste  in  any  given 
period  of  time.  But  denudation  and  deposition  must  be  equivalent  to 
each  other.  As  much  material  must  be  laid  down  in  sedimentary  accumu- 
lations as  has  been  mechanically  removed,  so  that  in  measuring  the 
annual  bulk  of  sediment  borne  into  the  sea  by  a  river,  we  obtain  a  clue 


not  only  to  the  rate  of  denudation  of  the  land,  but  also  to  the  rate  at 
which  the  deposition  of  new  sedimentary  formations  takes  place.  .  .  . 

But  in  actual  fact  the  testimony  in  favor  of  the  slow  accumulation  and 
high  antiquity  of  the  geological  record  is  much  stronger  than  might  be 
inferred  from  the  mere  thickness  of  the  stratified  formations.  These 
sedimentary  deposits  have  not  been  laid  down  in  one  unbroken  sequence, 
but  have  had  their  continuity  interrupted  again  and  again  by  upheaval 
and  depression.  So  fragmentary  are  they  in  some  regions  that  we  can 
easily  demonstrate  the  length  of  time  represented  there  by  still  existing 
sedimentary  strata  to  be  vastly  less  than  the  time  indicated  by  the  gaps  in 
the  series. 

There  is  yet  a  further  and  impressive  body  of  evidence  furnished  by 
the  successive  races  of  plants  and  animals  which  have  lived  upon  the 
earth  and  have  left  their  remains  sealed  up  within  its  rocky  crust.  No 
universal  destructions  of  organic  life  are  chronicled  in  the  stratified  rocks. 
It  is  everywhere  admitted  that,  from  the  remotest  times  up  to  the  pres- 
ent day,  there  has  been  an  onward  march  of  development,  type  succeed- 
ing type  in  one  long  continuous  progression.  As  to  the  rate  of  this  evolu- 
tion precise  data  are  wanting.  There  is,  however,  the  important  negative 
argument  furnished  by  the  absence  of  evidence  of  recognizable  specific 
variations  of  organic  forms  since  man  began  to  observe  and  record.  We 
know  that  within  human  experience  a  few  species  have  become  extinct, 
but  there  is  no  conclusive  proof  that  a  single  new  species  have  come  into 
existence,  nor  are  appreciable  variations  readily  apparent  in  forms  that 
live  in  a  wild  state.  The  seeds  and  plants  found  with  Egyptian  mummies, 
and  the  flowers  and  fruits  depicted  on  Egyptian  tombs,  are  easily  identi- 
fied with  the  vegetation  of  modern  Egypt.  The  embalmed  bodies  of 
animals  found  in  that  country  show  no  sensible  divergence  from  the 
structure  or  proportions  of  the  same  animals  at  the  present  day.  The 
human  races  of  Northern  Africa  and  Western  Asia  were  already  as 
distinct  when  portrayed  by  the  ancient  Egyptian  artists  as  they  are  now, 
and  they  do  not  seem  to  have  undergone  any  perceptible  change  since 
then.  Thus  a  lapse  of  four  or  five  thousand  years  has  not  been  accom- 
panied by  any  recognizable  variation  in  such  forms  of  plant  and  animal 
life  as  can  be  tendered  in  evidence.  Absence  of  sensible  change  in  these 
instances  is,  of  course,  no  proof  that  considerable  alteration  may  not  have 
been  accomplished  in  other  forms  more  exposed  to  vicissitudes  of 
climate  and  other  external  influences.  But  it  furnishes  at  least  a  presump- 
tion in  favor  of  the  extremely  tardy  progress  of  organic  variation. 

If,  however,  we  extend  our  vision  beyond  the  narrow  range  of  human 
history,  and  look  at  the  remains  of  the  plants  and  animals  preserved  in 

112  THE  EARTH 

those  younger  formations  which,  though  recent  when  regarded  as  parts 
of  the  whole  geological  record,  must  be  many  thousands  of  years  older 
than  the  very  oldest  of  human  monuments,  we  encounter  the  most 
impressive  proofs  of  the  persistence  of  specific  forms.  Shells  which  lived 
in  our  seas  before  the  coming  of  the  Ice  Age  present  the  very  same 
peculiarities  of  form,  structure,  and  ornament  which  their  descendants 
still  possess.  The  lapse  of  so  enormous  an  interval  of  time  has  not 
sufficed  seriously  to  modify  them.  So  too  with  the  plants  and  the  higher 
animals  which  still  survive.  Some  forms  have  become  extinct,  but  few 
or  none  which  remain  display  any  transitional  gradations  into  new 
species.  We  must  admit  that  such  transitions  have  occurred,  that  indeed 
they  have  been  in  progress  ever  since  organized  existence  began  upon 
our  planet,  and  are  doubtless  taking  place  now.  But  we  can  not  detect 
them  on  the  way,  and  we  feel  constrained  to  believe  that  their  march 
must  be  excessively  slow.  .  .  . 

If  the  many  thousands  of  years  which  have  elapsed  since  the  Ice  Age 
have  produced  no  appreciable  modification  of  surviving  plants  and 
animals,  how  vast  a  period  must  have  been  required  for  that  marvellous 
scheme  of  organic  development  which  is  chronicled  in  the  rocks!  .  .  . 

I  have  reserved  for  final  consideration  a  branch  of  the  history  of  the 
earth  which,  while  it  has  become,  within  the  lifetime  of  the  present 
generation,  one  of  the  most  interesting  and  fascinating  departments  of 
geological  inquiry,  owed  its  first  impulse  to  the  far-seeing  intellects  of 
Hutton  and  Playfair.  With  the  penetration  of  genius  these  illustrious 
teachers  perceived  that  if  the  broad  masses  of  land  and  the  great  chains 
of  mountains  owe  their  origin  to  stupendous  movements  which  from 
time  to  time  have  convulsed  the  earth,  their  details  of  contour  must  be 
mainly  due  to  the  eroding  power  of  running  water.  They  recognized 
that  as  the  surface  of  the  land  is  continually  worn  down,  it  is  essentially 
by  a  process  of  sculpture  that  the  physiognomy  of  every  country  has  been 
developed,  valleys  being  hollowed  out  and  hills  left  standing,  and  that 
these  inequalities  in  topographical  detail  are  only  varying  and  local 
accidents  in  the  progress  of  the  one  great  process  of  the  degradation  of 
the  land. 

From  the  broad  and  guiding  outlines  of  theory  thus  sketched  we 
have  now  advanced  amid  ever-widening  multiplicity  of  detail  into  a 
fuller  and  nobler  conception  of  the  origin  of  scenery.  The  law  of  evolu- 
tion is  written  as  legibly  on  the  landscapes  of  the  earth  as  on  any  other 
page  of  the  book  of  Nature.  Not  only  do  we  recognize  that  the  existing 
topography  of  the  continents,  instead  of  being  primeval  in  origin,  has 
gradually  been  developed  after  many  precedent  mutations,  but  we  are 


enabled  to  trace  these  earlier  revolutions  in  the  structure  of  every  hill 
and  glen.  Each  mountain  chain  is  thus  found  to  be  a  memorial  of  many 
successive  stages  in  geographical  evolution.  Within  certain  limits  land  and 
sea  have  changed  places  again  and  again.  Volcanoes  have  broken  out 
and  have  become  extinct  in  many  countries  long  before  the  advent  of 
man.  Whole  tribes  of  plants  and  animals  have  meanwhile  come  and 
gone,  and  in  leaving  their  remains  behind  them  as  monuments  at  once 
of  the  slow  development  of  organic  types,  and  of  the  prolonged  vicissi- 
tudes of  the  terrestrial  surface,  have  furnished  materials  for  a  chrono- 
logical arrangement  of  the  earth's  topographical  features.  Nor  is  it  only 
from  the  organisms  of  former  epochs  that  broad  generalizations  may  be 
drawn  regarding  revolutions  in  geography.  The  living  plants  and  animals 
of  to-day  have  been  discovered  to  be  eloquent  of  ancient  geographical 
features  that  have  long  since  vanished.  In  their  distribution  they  tell  us 
that  climates  have  changed;  that  islands  have  been  disjoined  from  con- 
tinents; that  oceans  once  united  have  been  divided  from  each  other,  or 
once  separate  have  now  been  joined;  that  some  tracts  of  land  have 
disappeared,  while  others  for  prolonged  periods  of  time  have  remained 
in  isolation.  The  present  and  the  past  are  thus  linked  together,  not 
merely  by  dead  matter,  but  by  the  world  of  living  things,  into  one  vast 
system  of  continuous  progression. 


Earthquakes — What  Are  They? 


certain  belts  in  which  earthquakes  occur  more  often  than  in  other 
parts  of  the  world.  Why  should  this  be  the  case?  We  read  from  time  to 
time  of  destructive  earthquakes  in  Japan.  But  many  lesser  shocks  occur  there 
of  which  we  never  hear.  In  fact,  there  is  an  earthquake,  large  or  small, 
somewhere  in  Japan  practically  every  day.  Similarly,  the  Kurile  Islands, 
the  Aleutian  Islands,  Alaska  and  the  Queen  Charlotte  Islands  are  subject 
to  frequent  earth  shocks.  Continuing  around  the  Pacific  circle,  we  meet 
with  many  earthquakes  in  California,  Mexico,  Central  America,  Vene- 
zuela, Colombia,  Ecuador,  Bolivia,  Peru  and  Chili.  And  on  the  other 
side  of  the  Pacific  Ocean,  the  earthquake  belt  continues  from  Japan 
southward  through  Formosa  and  the  Philippine  Deep  to  New  Zealand. 
Another  somewhat  less  striking  earthquake  zone  runs  from  Mexico  and 
the  Antilles  through  the  northern  Mediterranean  countries  and  Asia 
Minor  into  the  Pamirs,  Turkestan,  Assam  and  the  Indian  Ocean.  In  other 
parts  of  the  earth,  destructive  earthquakes  also  occur,  but  as  more  or  less 
isolated  phenomena.  Examples  in  this  country  are  the  Mississippi  Valley 
earthquakes  of  1811  and  of  the  following  year,  and  the  Charleston  earth- 
quake of  1886. 

Now  why  should  destructive  earthquakes  occur  more  frequently  in 
such  a  zone  or  belt  as  the  border  of  the  Pacific  Ocean?  What  is  an 
earthquake?  Centuries  ago,  many  people,  and  even  scientific  men, 
thought  that  earthquakes  were  caused  by  explosions  down  in  the  earth; 
and  there  have  not  been  wanting  men  in  our  own  time  who  held  this 
view.  Others,  like  Alexander  von  Humboldt,  thought  that  earthquakes 
were  connected  with  volcanoes;  that  the  earth  is  a  ball  of  molten  lava 
covered  by  a  thin  shell  of  rock  and  that  the  volcanoes  were  a  sort  of 
safety  valve.  As  long  as  the  volcanoes  are  active,  they  said,  the  pressure 
within  the  molten  lava  of  the  earth  is  held  down,  but  when  the  volcanoes 



cease  their  activity,  thus  closing  the  safety  valves,  so  to  speak,  the  increas- 
ing pressure  eventually  causes  a  fracture  in  the  earth's  crust.  Another 
theory  supposed  that  the  lava  occupied  passageways  in  a  more  or  less 
solid  portion  of  the  earth  underneath  the  crust  and  that  the  movement  of 
lava  within  these  passages  caused  such  pressure  as  to  burst  their  walls, 
thus  causing  an  earthquake. 

Quite  a  different  point  of  view  was  taken  by  those  who  held  the  theory 
that  earthquakes  occurred  within  the  uppermost  crust  of  the  earth.  This 
crust  was  supposed  to  be  honeycombed  with  vast  caves.  Even  the  whole 
mountain  chain  of  the  Alps  was  thought  to  be  an  immense  arch  built 
up  over  a  cavern.  When  the  arch  should  break,  thus  allowing  the  overly- 
ing rocks  to  drop  somewhat,  we  would  have  an  earthquake.  In  many 
cases,  those  who  held  this  theory  believed  that  the  entire  roof  would 
collapse  and  that  earthquakes  are  generally  due  to  the  impact  of  the 
falling  mass  of  rocks  on  the  floor  of  the  cavern. 

But  it  has  been  shown,  since  the  discovery  of  the  passage  of  earthquake 
waves  through  the  earth  and  their  registration  by  means  of  seismographs, 
that  the  outer  portion  of  the  earth  down  to  a  depth  of  at  least  five 
elevenths  of  the  earth's  radius  is  not  only  solid,  but,  with  the  exception  of 
the  outer  layers,  is  more  than  twice  as  rigid  as  steel  in  the  laboratory. 
It  has  also  been  shown  that  volcanoes  are  a  purely  surface  phenomenon; 
that  they  have  no  connection  with  each  other,  even  when  they  are  but 
a  few  miles  apart.  Hence  it  is  clear  that  earthquakes  connected  with 
volcanoes  must  be  of  very  local  character,  if  they  are  to  be  caused  by  the 
movement  of  lava.  This  is  found  to  be  actually  the  case.  It  is  also  clear 
that  some  other  cause  must  operate  in  producing  earthquakes,  since 
destructive  earthquakes  often  occur  very  far  from  volcanoes.  In  fact, 
some  regions  where  there  are  frequent  earthquakes  have  no  volcanoes 
at  all. 

In  the  California  earthquake  of  1906,  there  occurred  a  fracture  of  the 
earth's  crust  which  could  be  followed  at  the  surface  for  a  distance  of 
more  than  150  miles,  extending  from  the  Gualala  River  Valley  on  the 
northern  coast  of  California  southeastward  through  Tomales  Bay  and 
outside  the  Golden  Gate  to  the  old  mission  of  San  Juan  Bautista.  The 
rocks  on  the  east  side  of  this  fracture  moved  southeastward  relatively  to 
those  on  the  west  side,  so  that  every  road,  fence  or  other  structure  which 
had  been  built  across  the  line  of  fracture  was  offset  by  varying  amounts 
up  to  twenty-one  feet.  A  study  of  this  earthquake  led  scientific  men  to  the 
conclusion  that  the  mechanism  of  the  earthquake  was  an  elastic  rebound. 
It  was  thought  that  the  rocks  in  the  portion  of  the  earth's  crust  west  of 
the  fracture  had  been  draped  northward  until  the  ultimate  strength  of 

116  THE  EARTH 

the  rocks  was  reached  along  this  zone  of  weakness.  When  the  fracture 
occurred,  the  rocks,  like  bent  springs,  sprang  back  to  an  unstrained 
position.  But  this  did  not  occur  in  one  continuous  throw,  but  in  a  series 
of  jerks,  each  of  which  set  up  elastic  vibrations  in  the  rocks.  These 
vibrations  traveled  out  in  all  directions  and  constituted  the  earthquake 
proper.  The  zone  of  weakness  in  which  the  California  earthquake 
occurred  is  a  valley  known  as  the  San  Andreas  rift.  It  is  usually  quite 
straight  and  ignores  entirely  the  physiography  of  the  region,  passing 
indifferently  over  lowlands  and  mountains  and  extending  more  than  300 
miles  beyond  the  end  of  the  fracture  of  1906  until  it  is  lost  in  the  Colorado 
desert  east  of  San  Bernardino.  The  entire  floor  of  the  valley  has  been 
broken  up  by  earthquakes  occurring  through  the  ages  into  small  blocks 
and  ridges  and  even  into  rock  flour. 

The  San  Andreas  rift  is  only  one  of  the  many  features  which  parallel 
the  Pacific  Coast  in  California.  There  are  other  lesser  rifts  on  which 
earthquakes  have  occurred.  Similar  to  these  rifts  in  some  respects  are 
the  ocean  deeps,  along  the  walls  of  which  occur  some  of  the  world's 
most  violent  earthquakes. 

Why  do  these  features  parallel  the  Pacific  shore?  And  why  are  earth- 
quakes associated  with  them?  Both  seem  to  be  connected  in  some  way 
with  the  process  of  mountain-building,  for  many  of  the  features  in  this 
circum-Pacific  belt  are  geologically  recent.  Many  have  thought  that 
mountain-building  in  general  and  the  processes  going  on  around  the 
Pacific  in  particular  are  due  to  a  shortening  of  the  earth's  crust  caused  by 
gradual  cooling  of  the  interior  and  the  consequent  shrinkage,  but  this 
is  not  evident.  While  the  earth  is  surely  losing  heat  by  radiation  into 
space,  it  is  being  heated  by  physical  and  chemical  processes  connected 
with  radioactivity  at  such  a  rate  that,  unless  the  radioactive  minerals  are 
confined  to  the  uppermost  ten  miles  or  so  of  the  earth's  crust,  the  earth 
must  be  getting  hotter  instead  of  cooler,  because  the  amount  of  heat 
generated  must  exceed  that  which  is  conducted  to  the  surface  and  radiated 

Another  suggested  cause  of  earthquakes  is  isostatic  compensation.  If 
we  take  a  column  of  rock  extending  downward  from  the  top  of  a  moun- 
tain chain  to  a  given  level  within  the  earth's  crust  and  compare  it  with 
another  column  extending  to  the  same  level  under  a  plain,  the  mountain 
column  will  be  considerably  longer  than  the  other  and  consequently  will 
contain  more  rock.  Hence  it  should  weigh  more,  unless  the  rocks  of  which 
it  is  composed  are  lighter  than  those  under  the  plain,  but  geodesists  tell 
us  that  the  two  columns  weigh  the  same.  Hence  the  rocks  under  the 
plain  must  be  the  heavier  of  the  two.  But  even  if  this  is  the  case,  we 


should  expect  the  conditions  to  change;  for  rain  and  weather  are  continu- 
ally removing  rocks  from  the  tops  of  the  mountains  and  distributing  the 
materials  of  which  they  are  composed  over  the  plain.  Nevertheless, 
according  to  the  geodesists,  the  columns  continue  to  weigh  the  same. 
Hence  we  must  conclude  that  compensation  in  some  form  must  be  taking 
place.  There  must  be  an  inflow  of  rock  into  the  mountain  column  and 
an  outflow  from  the  plain  column.  But  the  cold  flow  of  a  portion  of  a 
mass  of  rock  must  place  enormous  strain  on  the  surrounding  portions. 
When  the  stress  reaches  the  ultimate  strength  of  the  rocks,  there  must  be 
fracture  and  a  relief  of  strain,  thus  causing  an  earthquake. 

It  has  recently  been  found  that  earthquakes  occur  at  considerable  depth 
in  the  earth.  Hence  they  can  not  be  caused  by  purely  surface  strains. 
There  are  a  few  earthquakes  which  seem  to  have  occurred  at  depths 
up  to  300  miles.  This  is  far  below  the  depth  of  compensation  of  the 
geodesists.  It  is  also  below  the  zone  of  fracture  of  the  geologists,  and  far 
down  in  what  they  call  the  zone  of  flow.  Can  an  earthquake  be  generated 
by  a  simple  regional  flow?  We  do  not  know,  but  it  would  seem  that 
sudden  release  of  strain  is  necessary  to  cause  the  vibrations  which  we 
call  an  earthquake.  It  may  be  that  a  strain  is  produced  and  gradually 
grows  in  such  a  way  as  to  produce  planes  of  shear  such  as  occur  when 
a  column  is  compressed  lengthwise.  These  planes  of  maximum  shear 
usually  form  an  angle  of  about  forty-five  degrees  with  the  direction  of 
the  force.  Recent  investigation  into  the  failure  of  steel  indicates  that  under 
certain  conditions  it  will  retain  its  full  strength  up  to  the  moment  of 
failure  when  the  steel  becomes  as  plastic  as  mud  along  the  planes  of 
maximum  shear.  The  two  portions  of  the  column  then  glide  over  each 
other  on  the  plastic  zone  until  the  strain  is  relieved,  whereupon  the  steel 
within  the  zone  becomes  hard  and  rigid  as  before.  It  may  be  that  a 
process  somewhat  similar  to  this  may  take  place  deep  down  in  the  earth, 
and  that  the  sheared  surface  may  be  propagated  upwards  through  the 
zone  of  flow  to  the  zone  of  fracture  and  even  to  the  surface  of  the  earth. 
In  that  case,  the  plastic  shear  would  give  way  to  true  fracture  near  the 

It  is  only  by  a  careful  study,  not  only  of  the  waves  produced  by  earth- 
quakes and  of  the  permanent  displacements  which  occur  in  them,  but  of 
the  actual  movement  along  the  planes  of  fracture,  that  we  shall  be  able 
to  discover  what  an  earthquake  really  is.  For  the  present,  we  must  be 
satisfied  with  knowing  that  it  is  an  elastic  process;  that  it  is  usually 
destructive  only  within  a  very  restricted  belt,  and  that  it  is  probably 
produced  by  the  sudden  release  of  a  regional  strain  within  the  crust  of 
the  earth. 

Last  Days  of  St.  Pierre 


From  Disaster  Fighters 



JL  JL  Clerc.  Little  past  the  age  of  forty,  in  this  year  of  1902,  he  was  the 
leading  planter  of  the  fair  island  of  Martinique.  Sugar  from  his  broad 
cane  fields,  molasses,  and  mellow  rum  had  made  him  a  man  of  wealth, 
a  millionaire.  All  his  enterprises  prospered. 

Were  the  West  Indies,  for  all  their  beauty  and  their  bounty,  sometimes 
powerless  to  prevent  a  sense  of  exile,  an  ache  of  homesickness  in  the 
heart  of  a  citizen  of  the  Republic?  Then  there  again  fate  had  been  kind 
to  Fernand  Clerc.  Elected  a  member  of  the  Chamber  of  Deputies,  it  was 
periodically  his  duty  and  his  pleasure  to  embark  and  sail  home  to  attend 
its  sessions — home  to  France,  to  Paris. 

Able,  respected,  good-looking,  blessed  with  a  charming  wife  and 
children,  M.  Clerc  found  life  good  indeed.  With  energy  undepleted  by 
the  tropics,  he  rode  through  the  island  visiting  his  properties.  Tall  and 
thick  grew  the  cane  stalks  of  his  plantation  at  Vive  on  the  slopes  of 
Mont  Pelee.  Mont  Pelee — Naked  Mountain — well  named  when  lava 
erupting  from  its  cone  had  stripped  it  bare  of  its  verdure.  But  that  was 
long  ago.  Not  since  1851  had  its  subterranean  fires  flared  up  and  then 
but  insignificantly.  Peaceful  now,  its  crater  held  the  lovely  Lake  of 
Palms,  whose  wooded  shores  were  a  favorite  picnic  spot  for  parties  from 
St.  Pierre  and  Fort-de-France.  Who  need  fear  towering  Mont  Pelee,  once 
mighty,  now  mild,  an  extinct  volcano? 

Yet  this  spring  M.  Clerc  and  all  Martinique  received  a  rude  shock. 
The  mountain  was  not  dead,  it  seemed.  White  vapors  veiled  her  sum- 
mit, and  by  May  2nd  she  had  overlaid  her  green  mantle  with  a  gown 



of  gray  cinders.  Pelee  muttered  and  fumed  like  an  angry  woman  told 
her  day  was  long  past.  Black  smoke  poured  forth,  illumined  at  night  by 
jets  of  flame  and  flashes  of  lightning.  The  grayish  snow  of  cinders  covered 
the  countryside,  and  the  milky  waters  of  the  Riviere  Blanche  altered  into 
a  muddy  and  menacing  torrent. 

Nor  was  Pelee  uttering  only  empty  threats.  On  May  5th,  M.  Clerc  at 
Vive  beheld  a  cloud  rolling  from  the  mountain  down  the  valley.  Sparing 
his  own  acres,  the  cloud  and  the  stream  of  smoking  lava  which  it  masked, 
enveloped  the  Guerin  sugar  factory,  burying  its  owner,  his  wife,  over- 
seer, and  twenty-five  workmen  and  domestics. 

Dismayed  by  this  tragedy,  M.  Clerc  and  many  others  moved  from  the 
slopes  into  St.  Pierre.  The  city  was  crowded,  its  population  of  25,000 
swollen  to  40,000,  and  the  throngs  that  filled  the  market  and  the  cafes 
or  strolled  through  the  gorgeously  luxuriant  Jardin  des  Plantes  lent  an 
air  of  added  animation,  of  almost  hectic  gaiety.  When  M.  Clerc  professed 
alarm  at  the  behavior  of  Pelee  to  his  friends,  he  was  answered  with 
shrugs  of  shoulders.  Danger?  On  the  slopes  perhaps,  but  scarcely  here  in 
St.  Pierre  down  by  the  sea. 

Thunderous,  scintillant,  Mont  Pelee  staged  a  magnificent  display  of 
natural  fireworks  on  the  night  of  May  7th.  Whites  and  negroes  stared  up 
at  it,  fascinated.  Some  were  frightened  but  more  took  a  child-like  joy 
in  the  vivid  spectacle.  It  was  as  if  the  old  volcano  were  celebrating  the 
advent  of  tomorrow's  fete  day. 

M.  Fernand  Clerc  did  not  sleep  well  that  night.  He  breakfasted  early 
in  the  household  where  he  and  his  family  were  guests  and  again  expressed 
his  apprehensions  to  the  large  group  of  friends  and  relatives  gathered 
at  the  table.  Politely  and  deferentially — for  one  does  not  jeer  a  personage 
and  man  of  proven  courage — they  heard  him  out,  hiding  their  scepticism. 

The  voice  of  the  planter  halted  in  mid-sentence;  and  he  half  rose,  his 
eyes  fixed  on  the  barometer.  Its  needle  was  actually  fluttering! 

M.  Clerc  pushed  back  his  chair  abruptly  and  commanded  his  carriage 
at  once.  A  meaning  look  to  his  wife  and  four  children,  and  they  hastened 
to  make  ready.  Their  hosts  and  the  rest  followed  them  to  the  door.  Nonf 
merely  none  would  join  their  exodus.  Au  revoir.  A  demain. 

From  the  balcony  of  their  home,  the  American  Consul,  Thomas 
Prentis,  and  his  wife  waved  to  the  Clerc  family  driving  by.  "Stop,"  the 
planter  ordered  and  the  carriage  pulled  up.  Best  come  along,  the  planter 
urged.  His  American  friends  thanked  him.  There  was  no  danger,  they 
laughed,  and  waved  again  to  the  carriage  disappearing  in  gray  dust  as 
racing  hoofs  and  wheels  sped  it  out  of  the  city  of  St.  Pierre. 

120  THE  EARTH 


Governor  Mouttet,  ruling  Martinique  for  the  Republic  of  France, 
glared  up  at  rebellious  Mont  Pelee.  This  peste  of  a  volcano  was  deranging 
the  island.  There  had  been  no  such  crisis  since  its  captures  by  the  English, 
who  always  relinquished  it  again  to  France,  or  the  days  when  the  slaves 
revolted.  A  great  pity  that  circumstances  beyond  his  control  should  dam- 
age the  prosperous  record  of  his  administration,  the  Governor  reflected. 

That  miserable  mountain  was  disrupting  commerce.  Its  rumblings 
drowned  out  the  band  concerts  in  the  Savane.  Its  pyrotechnics  distracted 
glances  which  might  far  better  have  dwelt  admiringly  on  the  proverbial 
beauty  of  the  women  of  Martinique. . .  .  Now  attention  was  diverted  to  a 
cruder  work  of  Nature,  a  sputtering  volcano.  Parbleul  It  was  enough 
to  scandalize  any  true  Frenchman. 

Governor  Mouttet  sighed  and  pored  over  the  reports  laid  before  him. 
He  had  appointed  a  commission  to  study  the  eruption  and  get  at  the 
bottom  of  I'affaire  Pelee,  but  meanwhile  alarm  was  spreading.  People 
were  fleeing  the  countryside  and  thronging  into  St.  Pierre,  deserting  that 
city  for  Fort-de-France,  planning  even  to  leave  the  island.  Steamship 
passage  was  in  heavy  demand.  The  Roraima,  due  May  8th,  was  booked 
solid  out  of  St.  Pierre,  one  said.  This  would  never  do.  Steps  must  be 
taken  to  prevent  a  panic  which  would  scatter  fugitives  throughout  Mar- 
tinique or  drain  a  colony  of  France  of  its  inhabitants. 

A  detachment  of  troops  was  despatched  by  the  Governor  to  St.  Pierre 
to  preserve  order  and  halt  the  exodus.  His  Excellency,  no  man  to  send 
others  where  he  himself  would  not  venture,  followed  with  Mme.  Mouttet 
and  took  up  residence  in  that  city.  Certainly  his  presence  must  serve  to 
calm  these  unreasoning,  exaggerated  fears.  He  circulated  among  the 
populace,  speaking  soothing  words.  Mes  enfants,  the  Governor  avowed, 
Mont  Pelee  rumbling  away  there  is  only  snoring  soundly  in  deep  slum- 
ber. Be  tranquil. 

Yet,  on  the  ominous  night  of  May  7th,  as  spurts  of  flame  painted  the 
heavens,  the  Governor  privately  confessed  to  inward  qualms.  What  if 
the  mountain  should  really  rouse?  Might  it  not  then  cast  the  mortals  at 
its  feet  into  a  sleep  deeper  than  its  own  had  been,  a  sleep  from  which 
they  would  never  awaken? 


Ellery  S.  Scott,  chief  officer  of  the  Quebec  Line  steamship  Roraima, 
stood  on  the  bridge  with  Captain  Muggah  as  the  vessel  bore  down  on 
Martinique.  A  column  of  smoke  over  the  horizon  traced  down  to  the 


4,500-foot  summit  of  Mont  Pelee.  So  the  old  volcano  was  acting  up! 
Curiosity  on  the  bridge  ran  high  as  anchor  was  dropped  in  the  St.  Pierre 
roadstead  about  6  o'clock  on  the  morning  of  May  8th.  But  all  seemed  well 
ashore.  The  streets,  twisting  and  climbing  between  the  bright-colored 
houses,  were  filled  with  crowds  in  gay  holiday  attire. 

Promptly  the  agents  came  aboard.  The  volcano?  But  certainly  it  was 
erupting  and  causing  inconvenience.  But  there  was  no  danger,  regardless 
of  the  opinion  of  that  Italian  skipper  yesterday  who  had  said  that  had 
he  seen  Vesuvius  looking  like  Pelee,  he  would  have  departed  from 
Naples  as  fast  as  he  was  going  to  leave  St.  Pierre.  Although  the  authorities 
refused  him  clearance  and  threatened  penalties,  he  had  sailed  in  haste, 
with  only  half  his  cargo. 

By  the  way,  the  agents  continued,  the  passenger  list  was  to  be  consid- 
erably augmented:  sixty  first-class  anxious  to  leave  St.  Pierre.  Here  they 
were  boarding  now  with  bag  and  baggage.  Could  they  be  humored,  and 
the  Roraima  sail  for  St.  Lucia  at  once,  returning  to  discharge  its  Mar- 
tinique cargo?  the  agents  inquired  of  Captain  Muggah. 

Chief  Officer  Scott,  ordered  below  to  inspect  the  stowage,  thought  of 
his  boy  in  the  forecastle.  A  good  lad  this  eldest  son  of  his.  Used  to  say 
he'd  have  a  ship  of  his  own  some  day  and  keep  on  his  father  as  first  mate. 
No,  his  father  planned  a  better  career  than  the  sea  for  him.  The  boy  was 
slated  to  go  to  college  and  be  a  lawyer.  This  would  be  his  last  voyage. 

Stowed  shipshape  and  proper  as  Scott  knew  he  would  find  it,  the 
cargo  plainly  could  not  be  shifted  without  a  good  deal  of  difficulty.  The 
Martinique  consignment  lay  above  that  for  St.  Lucia,  and  it  would  be 
a  heavy  task  to  discharge  at  the  latter  port  first.  Scott  so  reported. 

The  agents  hesitated  briefly.  To  be  sure,  sixty  first-class  passengers  were 
to  be  obliged  if  possible  but — ah,  well,  let  them  wait  a  little  longer.  The 
Roraima  would  sail  as  soon  as  the  upper  layer  of  cargo  was  landed. 

Ship's  bells  tolled  the  passing  hours.  Pelee  yonder  growled  hoarsely  and 
belched  black  smoke.  A  little  before  8,  Chief  Officer  Scott  apprehensively 
turned  his  binoculars  on  the  summit. 


It  was  dark  in  the  underground  dungeon  of  the  St.  Pierre  prison,  but 
thin  rays  of  light  filtered  through  the  grated  opening  in  the  upper  part 
of  the  cell  door.  Enough  so  that  Auguste  Ciparis  could  tell  when  it  was 
night  and  when  it  was  day. 

Not  that  it  mattered  much  unless  a  man  desired  to  count  the  days 
until  he  should  be  free.  What  good  was  that  ?  One  could  not  hurry  them 
by.  Therefore  Auguste  stolidly  endured  them  with  the  long  patience 

122  THE  EARTH 

of  Africa.  The  judge  had  declared  him  a  criminal  and  caused  him  to 
be  locked  up  here.  Thus  it  was  settled  and  nothing  was  to  be  done.  Yet 
it  was  hard,  this  being  shut  out  of  life  up  there  in  the  gay  city — hard 
when  one  was  only  twenty-five  and  strong  and  lusty. 

Auguste  slept  and  dozed  all  he  could.  Pelee  was  rumbling  away  in  the 
distance — each  day  the  jailer  bringing  him  food  and  water  seemed  more 
excited  about  it — but  the  noise,  reaching  the  subterranean  cell  only  as 
faint  thunder,  failed  to  keep  the  negro  awake.  .  .  . 

Glimmerings  of  the  dawn  of  May  8th  filtered  through  the  grating  into 
the  cell,  and  Auguste  stirred  into  wakefulness.  This  being  a  fete  day, 
imprisonment  was  less  tolerable.  What  merriment  his  friends  would  be 
making  up  there  in  the  squares  of  St.  Pierre!  He  could  imagine  the  side- 
long glances  and  the  swaying  hips  of  the  mulatto  girls  he  might  have 
been  meeting  today.  Auguste  stared  sullenly  at  the  cell  door.  At  least  the 
jailer  might  have  been  on  time  with  his  breakfast. 

The  patch  of  light  in  the  grating  winked  out  into  blackness.  Ail  Ait 
All  of  a  sudden  it  was  night  again. 

On  the  morning  of  May  8th,  1902,  the  clocks  of  St.  Pierre  ticked  on 
toward  ten  minutes  of  8  when  they  would  stop  forever.  Against  a  back- 
ground of  bright  sunshine,  a  huge  column  of  vapor  rose  from  the  cone  of 
Mont  Pelee. 

A  salvo  of  reports  as  from  heavy  artillery.  Then,  choked  by  lava  boiled 
to  white  heat  by  fires  in  the  depths  of  the  earth,  Pelee  with  a  terrific 
explosion  blew  its  head  off. 

Like  a  colossal  Roman  candle  it  shot  out  streaks  of  flame  and  fiery 
globes.  A  pall  of  black  smoke  rose  thousands  of  feet  in  the  air,  darkening 
the  heavens.  Silhouetted  by  a  red,  infernal  glare,  Pelee  flung  aloft  viscid 
masses  which  rained  incandescent  ashes  on  land  and  sea. 

Then,  jagged  and  brilliant  as  the  lightning  flashes,  a  fissure  opened  in 
the  flank  of  the  mountain  toward  St.  Pierre.  Out  of  it  issued  an  immense 
cloud  which  rushed  with  unbelievable  rapidity  down  on  the  doomed  city 
and  the  villages  of  Carbet  and  Le  Precheur. 

In  three  minutes  that  searing,  suffocating  cloud  enveloped  them,  and 
40,000  people  died! 

Fernand  Clerc,  the  planter,  watched  from  Mont  Parnasse,  one  mile 
east  of  St.  Pierre,  where  he  had  so  recently  breakfasted.  Shrouded  in  such 
darkness  as  only  the  inmost  depths  of  a  cavern  afford,  he  reached  out 
for  the  wife  and  children  he  could  not  see  and  gathered  them  in  blessed 
safety  into  his  arms.  But  the  relatives,  the  many  friends  he  had  left  s& 


short  a  while  ago,  the  American  consul  and  his  wife,  who  had  waved  him 
a  gay  good-by — them  he  would  never  see  alive  again.  .  .  . 

In  that  vast  brazier  which  was  St.  Pierre,  Governor  Mouttet  may  have 
lived  the  instant  long  enough  to  realize  that  Pelee  had  in  truth  awakened 
and  that  eternal  sleep  was  his  lot  and  his  wife's  and  that  of  all  those 
whose  flight  he  had  discouraged.  .  .  . 

Down  in  that  deep  dungeon  cell  of  his  Auguste  Ciparis  blinked  in  the 
swift-fallen  night.  Through  the  grating  blew  a  current  of  burning  air, 
scorching  his  flesh.  He  leaped,  writhing  in  agony  and  screaming  for  help. 
No  one  answered. 

Leaving  a  blazing  city  in  its  wake,  the  death  cloud  from  the  volcano 
rolled  over  the  docks,  and  the  sea,  hissing  and  seething,  shrank  back 
before  it.  Aboard  the  Roraima,  Chief  Officer  Scott  lowered  his  glasses 
precipitately  from  Pelee.  One  look  at  that  cloud  bearing  down  like  a 
whirlwind  and  he  snatched  a  tarpaulin  from  a  ventilator  and  pulled  it 
over  him.  The  ship  rolled  to  port,  almost  on  her  beam  ends,  then  back 
to  starboard.  Her  funnels  and  other  superstructure  and  most  of  her  small 
boats  were  swept  off  by  the  mighty  blast  laden  with  scalding  ashes  and 
stone  dust.  Badly  scorched,  Scott  emerged  from  his  refuge  to  catch  a 
glimpse  of  the  British  steamer  Roddam  plunging  by  toward  the  open  sea, 
her  decks  a  smoking  shambles.  Of  the  other  sixteen  vessels  which  had 
been  anchored  in  the  roadstead  there  was  no  sign. 

Staggering  toward  the  twisted  iron  wreckage  of  the  bridge,  the  Chief 
Officer  beheld  the  swaying  figure  of  Captain  Muggah.  From  the  hideous, 
blackened  mask  that  had  been  his  face  a  voice  croaked: 

"All  hands!  Heave  up  the  anchor!" 

All  hands!  Only  Scott,  two  engineers,  and  a  few  members  of  the  black 
gang  who  had  been  below  responded.  In  vain  Scott  scanned  the  group  for 
his  son.  He  never  saw  the  lad  again. 

The  anchor  could  not  be  unshackled.  "Save  the  women  and  children," 
the  captain  ordered.  During  attempts  to  lower  a  boat,  the  captain  disap- 
peared. Later  he  was  pulled  out  of  the  water  in  a  dying  condition. 

Now  the  Roraima  was  afire  fore  and  aft.  Amid  the  shrieks  and  groans 
of  dying  passengers,  Scott  and  three  more  able-bodied  men  fought  the 
flames,  helped  by  a  few  others  whose  hands,  burned  raw,  made  it  torture 
to  touch  anything.  Between  dousing  the  fire  with  bucketfuls  from  the 
sea,  Scott  tried  to  give  drinks  of  fresh  water  to  those  who  begged  pitifully 
for  it,  though  their  seared,  swollen  throats  would  not  let  them  swallow  a 
drop.  Tongues  lolling,  they  dragged  themselves  along  the  deck,  following 
him  like  dogs. 

When  the  French  cruiser  Suchct  steamed  up  to  the  rescue,  the  only 

124  THE  EARTH 

survivors  among  the  passengers  were  a  little  girl  and  her  nurse.  Twenty- 
eight  out  of  a  crew  of  forty-seven  were  dead. 

The  eyes  of  all  aboard  the  Suchet  turned  toward  shore.  There  at  the 
foot  of  a  broad,  bare  pathway,  paved  by  death  and  destruction  down  the 
slope  of  Mont  Pelee,  lay  the  utter  ruins  of  the  city  of  St.  Pierre. 


Not  until  the  afternoon  of  May  8th  did  the  devastation  of  St.  Pierre 
cool  sufficiently  to  allow  rescuers  from  Fort-de-France  to  enter.  They 
could  find  none  to  rescue  except  one  woman  who  died  soon  after  she 
was  taken  from  a  cellar. 

"St.  Pierre,  that  city  this  morning  alive,  full  of  human  souls,  is  no 
morel"  Vicar-General  Parel  wrote  his  Bishop.  "It  lies  consumed  before 
us,  in  its  windingsheet  of  smoke  and  cinders,  silent  and  desolate,  a  city 
of  the  dead.  We  strain  our  eyes  for  fleeing  inhabitants,  for  men  return- 
ing to  bury  their  lost  ones.  We  see  no  one!  There  is  no  living  being  left 
in  this  desert  of  desolation,  framed  in  a  terrifying  solitude.  In  the  back- 
ground, when  the  cloud  of  smoke  and  cinders  breaks  away,  the  moun- 
tain and  its  slopes,  once  so  green,  stand  forth  like  an  Alpine  landscape. 
They  look  as  if  they  were  covered  with  a  heavy  cloak  of  snow,  and 
through  the  thickened  atmosphere  rays  of  pale  sunshine,  wan,  and 
unknown  to  our  latitudes,  illumine  this  scene  with  a  light  that  seems 
to  belong  to  the  other  side  of  the  grave." 

Indeed  St.  Pierre  might  have  been  an  ancient  town,  destroyed  in 
some  half-forgotten  cataclysm  and  recently  partly  excavated— another 
Pompeii  and  Herculaneum.  Cinders,  which  had  buried  its  streets  six 
feet  deep  in  a  few  minutes,  were  as  the  dust  of  centuries.  Here  was  the 
same  swift  extinction  Vesuvius  had  wrought. 

Here  was  no  slow  flow  of  lava.  That  cloud  disgorged  by  Pelee  was  a 
superheated  hurricane  issuing  from  the  depths  of  the  earth  at  a  speed 
of  ninety  miles  an  hour.  Such  was  the  strength  of  the  blast,  it  killed 
by  concussion  and  by  toppling  walls  on  its  victims.  The  fall  of  the 
fourteen-foot  metal  statue  of  Notre  Dame  de  la  Garde— Our  Lady  of 
Safety— symbolized  the  dreadful  fact  that  tens  of  thousands  never  had  a 
fighting  chance  for  their  lives. 

But  chiefly  the  death  cloud  slew  with  its  lethal  content  of  hot  steam 
and  dust.  So  swiftly  did  it  pass  that  its  heat  did  not  always  burn  all  of 
the  light  tropical  clothing  from  its  prey,  but  once  it  was  inhaled  into 
the  lungs— that  was  the  end.  Some  had  run  a  few  frantic  steps;  then 
dropped,  hands  clutched  over  nose  and  mouth.  Encrusted  by  cement- 
like  ashes,  corpses  lay  fixed  in  the  contorted  postures  of  their  last  struggle 


replicas  of  the  dead  of  Vesuvius  preserved  in  the  Naples  museum.  Fire 
had  charred  others  or  incinerated  them  to  a  heap  of  bones.  A  horrible 
spectacle  was  presented  by  bodies  whose  skulls  and  abdomens  had  been 
burst  by  heat  and  gases. 

People  who  had  been  indoors  when  the  cloud  descended  perished 
where  they  stood  or  sat,  but  the  hand  of  death  had  marked  most  of  them 
less  cruelly.  They  seemed  almost  still  alive,  as  each  shattered  building 
disclosed  its  denouement.  There  a  girl  lay  prone,  her  arms  about  the 
feet  of  an  image  of  the  Virgin.  A  man  bent  with  his  head  thrust  into 
a  basin  from  which  the  water  had  evaporated.  A  family  was  gathered 
around  a  restaurant  table.  A  child  held  a  doll  in  her  arms;  when  the 
doll  was  touched,  it  crumbled  away  except  for  its  china  eyes.  A  clerk 
sat  at  his  desk,  one  hand  supporting  his  chin,  the  other  grasping  a  pen. 
A  baker  crouched  in  the  fire  pit  under  his  oven.  In  one  room  of  a 
home  a  blonde  girl  in  her  bathrobe  leaned  back  in  a  rocking-chair. 
Behind  her  stood  a  negro  servant  who  apparently  had  been  combing  the 
girl's  hair.  Another  servant  had  crawled  under  a  sofa.  Not  far  away 
lay  the  body  of  a  white  woman,  beautiful  as  a  Greek  statue,  and — like 
many  an  antique  statue — headless. 

Mutilated  or  almost  unmarred,  shriveled  in  last  agony  or  seeming  only 
to  have  dropped  into  a  peaceful  sleep,  lay  the  legions  of  the  dead.  After 
the  finding  of  the  dying  woman  in  a  cellar,  the  devastation  was  searched 
in  vain  for  survivors. 

Then  four  days  after  the  catastrophe,  two  negroes  walking  through  the 
wreckage  turned  gray  as  they  heard  faint  cries  for  help  issuing  from  the 
depths  of  the  earth. 

"Who's  that?"  they  shouted  when  they  could  speak.  " Where  are  you?" 

Up  floated  the  feeble  voice:  "I'm  down  here  in  the  dungeon  of  the  jail. 
Help!  Save  me!  Get  me  out!" 

They  dug  down  through  the  debris,  broke  open  the  dungeon  door, 
and  released  Auguste  Ciparis,  the  negro  criminal. 

Some  days  later,  George  Kennan  and  August  F.  Jaccaci,  American 
journalists  arriving  to  cover  the  disaster,  located  Ciparis  in  a  village  in  the 
country.  They  secured  medical  attention  for  his  severe  burns,  poorly 
cared  for  as  yet,  and  obtained  and  authenticated  his  story.  When  the 
scorching  air  penetrated  his  cell  that  day,  he  smelled  his  own  body  burn- 
ing but  breathed  as  little  as  possible  during  the  moment  the  intense  heat 
lasted.  Ignorant  of  what  had  occurred,  not  realizing  that  he  was  buried 
alive,  he  slowly  starved  for  four  days  in  his  tomb  of  a  cell.  His  scant 
supply  of  water  was  soon  gone.  Only  echoes  answered  his  shouts  for 

126  THE  EARTH 

help.  When  at  last  he  was  heard  and  freed,  Ciparis,  given  a  drink  of  water, 
managed  with  some  assistance  to  walk  six  kilometers  to  Morne  Rouge. 

One  who  lived  where  40,000  died!  History  records  no  escape  more 


Man,  Maker  of  Wilderness 


From  Deserts  on  the  March 


-*L  always  been.  To  earth  each  living  thing  restores  when  it  dies  that 
which  has  been  borrowed  to  give  form  and  substance  to  its  brief  day  in 
the  sun.  From  earth,  in  due  course,  each  new  living  being  receives  back 
again  a  loan  of  that  which  sustains  life.  What  is  lent  by  earth  has  been  used 
by  countless  generations  of  plants  and  animals  now  dead  and  will  be 
required  by  countless  others  in  the  future.  In  the  case  of  an  element  such 
as  phosphorus,  so  limited  is  the  supply  that  if  it  were  not  constantly  being 
returned  to  the  soil,  a  single  century  would  be  sufficient  to  produce  a 
disastrous  reduction  in  the  amount  of  life.  No  plant  or  animal,  nor  any 
sort  of  either,  can  establish  permanent  right  of  possession  to  the  materials 
which  compose  its  physical  body. 

Left  to  herself,  nature  manages  these  loans  and  redemptions  in  not 
unkindly  fashion.  She  maintains  a  balance  which  will  permit  the  briefest 
time  to  elapse  between  burial  and  renewal.  The  turnover  of  material  for 
new  generations  to  use  is  steady  and  regular.  Wind  and  water,  those  twin 
sextons,  do  their  work  as  gently  as  may  be.  Each  type  of  plant  and  animal, 
so  far  as  it  is  fit,  has  its  segment  of  activity  and  can  bring  forth  its  own  kind 
to  the  limits  of  subsistence.  The  red  rule  of  tooth  and  claw  is  less  harsh 
in  fact  than  in  seeming.  There  is  a  balance  in  undisturbed  nature  between 


food  and  feeder,  hunter  and  prey,  so  that  the  resources  of  the  earth  are 
never  idle.  Some  plants  or  animals  may  seem  to  dominate  the  rest,  but 
they  do  so  only  so  long  as  the  general  balance  is  maintained.  The  whole 
world  of  living  things  exists  as  a  series  of  communities  whose  order  and 
permanence  put  to  shame  all  but  the  most  successful  of  human  enterprises. 

It  is  into  such  an  ordered  world  of  nature  that  primitive  man  fits  as  a 
part.  A  family  of  savage  man,  living  by  the  chase  and  gathering  wild 
plants,  requires  a  space  of  ten  to  fifty  square  miles  for  subsistence.  If 
neighbors  press  too  closely,  the  tomahawk  of  tribal  warfare  offers  a  rude 
but  perhaps  merciful  substitute  for  starvation.  Man  in  such  a  stage  takes 
what  he  can  get  on  fairly  even  terms  with  the  rest  of  nature.  Wind  and 
water  may  strike  fear  to  his  heart  and  even  wreak  disaster  upon  him,  but 
on  the  whole  their  violence  is  tempered.  The  forces  of  nature  expend 
themselves  beneficently  upon  the  highly  developed  and  well  balanced 
forests,  grasslands,  even  desert.  To  the  greatest  possible  extent  the  surface 
consists  of  mellow,  absorbent  soil,  anchored  and  protected  by  living  plants 
— a  system  buffered  against  the  caprice  of  the  elements,  although  of  course 
subject  to  slow  and  orderly  change.  Bare  ground  left  by  the  plow  will 
have  as  much  soil  washed  off  in  ten  years  as  the  unbroken  prairie  will  lose 
in  four  thousand.  Even  so,  soil  in  the  prairie  will  be  forming  as  fast  as, 
or  faster  than  it  is  lost. 

Living  in  such  a  setting,  man  knows  little  or  nothing  of  nature's  laws, 
yet  conforms  to  them  with  the  perfection  over  which  he  has  no  more  choice 
than  the  oaks  and  palms,  the  cats  and  reptiles  around  him.  Gradually, 
however,  and  with  many  halting  steps,  man  has  learned  enough 
about  the  immutable  laws  of  cause  and  effect  so  that  with  tools, 
domestic  animals,  and  crops  he  can  speed  up  the  processes  of  nature 
tremendously  along  certain  lines.  The  rich  Nile  Valley  can  be  made  to  sup- 
port, not  one,  but  one  thousand  people  per  square  mile,  as  it  does  today. 
Cultures  develop,  cities  and  commerce  flourish,  hunger  and  fear  dwindle 
as  progress  and  the  conquest  of  nature  expand.  Unhappily,  nature  is  not 
so  easily  thwarted.  The  old  problems  of  population  pressure  and  tribal 
warfare  appear  in  newer  and  more  horrible  guise,  with  whole  nations 
trained  for  slaughter.  And  back  of  it  all  lies  the  fact  that  man  has  upset 
the  balance  under  which  wind  and  water  were  beneficial  agents  of  con- 
struction, to  release  them  as  twin  demons  which  carve  the  soil  from 
beneath  his  feet,  to  hasten  the  decay  and  burial  of  his  handiwork. 

Nature  is  not  to  be  conquered  save  on  her  own  terms.  She  is  not  con- 
ciliated by  cleverness  or  industry  in  devising  means  to  defeat  the  operation 
of  one  of  her  laws  through  the  workings  of  another.  She  is  a  very  busi- 
ness-like old  lady,  who  plays  no  favorites.  Man  is  welcome  to  outnumber 

128  THE  EARTH 

and  dominate  the  other  forms  of  life,  provided  he  can  maintain  order 
among  the  relentless  forces  whose  balanced  operation  he  has  disturbed. 
But  this  hard  condition  is  one  which,  to  date,  he  has  scarcely  met.  His  own 
past  is  full  of  clear  and  somber  warnings — vanished  civilizations  like  dead 
flies  in  lacquer,  buried  beneath  their  own  dust  and  mud. 

For  man,  who  fancies  himself  the  conqueror  of  it,  is  at  once  the  maker 
and  the  victim  of  the  wilderness.  Even  the  dense  and  hostile  jungles 
of  the  tropics  are  often  the  work  of  his  hands.  The  virgin  forest  of  the 
tropics,  as  of  other  climes,  is  no  thicket  of  scrub  and  thorn,  but  a  cathe- 
dral of  massive,  well-spaced  giant  trees  under  whose  dense  canopy  the 
alien  and  tangled  rabble  of  the  jungle  does  not  thrive.  Order  and  per- 
manence are  here — these  giants  bring  forth  young  after  their  own  kind, 
but  only  so  fast  as  death  and  decay  break  the  solid  ranks  of  the  elders. 
Let  man  clear  these  virgin  forests,  even  convert  them  into  fields,  he  can 
scarcely  keep  them.  Nature  claims  them  again,  and  her  advance  guards 
are  the  scrambled  barriers  through  which  man  must  chop  his  way. 

In  the  early  centuries  of  the  present  era,  while  the  Roman  Empire  was 
cracking  to  pieces,  the  Mayas  built  great  cities  in  Central  America.  Their 
huge  pyramids,  massive  masonry,  and  elaborate  carving  are  proof  of  capac- 
ity and  leisure.  They  also  indicate  that  the  people  who  built  them  prob- 
ably felt  a  sense  of  security,  permanence,  and  accomplishment  as  solid  as 
our  own.  To  them  the  end  of  their  world  was  no  doubt  unthinkable  save 
as  a  device  of  priestly  dialectic,  or  an  exercise  of  the  romantic  imagination. 
Food  there  was  in  abundance,  furnished  by  the  maize,  cacao,  beans, 
and  a  host  of  other  plants  of  which  southern  Mexico  is  the  first  home. 
Fields  were  easily  cleared  by  girdling  trees  with  sharp  stone  hatchets.  You 
can  write  your  name  on  plate  glass  with  their  little  jadeite  chisels.  The 
dead  trees  were  then,  as  they  are  today  in  Yucatan,  destroyed  by  fire, 
and  crops  were  planted  in  their  ashes. 

Yet  by  the  sixth  century  all  of  this  was  abandoned  and  the  Second 
Empire  established  northward  in  Yucatan,  to  last  with  varying  fortunes 
until  the  Spanish  conquest.  Pyramids  and  stonework  became  the  play- 
ground of  the  jungle,  so  hidden  and  bound  beneath  its  knotted  mesh 
that  painful  labor  has  been  required  to  reveal  what  is  below.  Farther 
north  in  Yucatan,  in  humble  villages,  are  the  modern  people,  unable  to 
read  the  hieroglyphs  of  their  ancestors,  and  treasuring  only  fragments  of 
the  ancient  lore  which  have  survived  by  word  of  mouth.  There  persists 
among  these  people,  for  example,  a  considerable  body  of  knowledge  con- 
cerning medicinal  plants,  their  properties  and  mode  of  use.  But  the  power 
and  glory  of  the  cities  is  gone.  In  their  place  are  only  ruins  and  wilderness. 


Their  world,  once  so  certain,  stable,  dependable,  and  definite,  is  gone. 
And  why? 

Here  of  course,  is  a  first-rate  mystery  for  modern  skill  and  knowledge 
to  unravel.  The  people  were  not  exterminated,  nor  their  cities  taken  over 
by  an  enemy.  Plagues  may  cause  temporary  migrations,  but  not  the  perma- 
nent abandonment  of  established  and  prosperous  centers.  The  present 
population  to  the  north  has  its  share  of  debilitating  infections,  but  its 
ancestors  were  not  too  weak  or  wasted  to  establish  the  Second  Empire 
after  they  left  the  First.  Did  the  climate  in  the  abandoned  cities  become  so 
much  more  humid  that  the  invasion  of  dense  tropical  vegetation  could  not 
be  arrested,  while  fungous  pests,  insects,  and  diseases  took  increasing  toll  ? 
This  is  hard  to  prove.  Were  the  inhabitants  starved  out  because  they  had 
no  steel  tools  or  draft  animals  to  break  the  heavy  sod  which  formed  over 
their  resting  fields?  Many  experts  think  so. 

Certainly  the  soil  of  the  wet  tropics  is  very  different  from  the  deep  rich 
black  soil  of  the  prairies.  Just  as  soaking  removes  salt  from  a  dried 
mackerel,  so  the  nourishing  minerals  are  quickly  removed  from  these  soils 
by  the  abundant  water.  In  the  steaming  hot  climate  the  plant  and  animal 
materials  which  fall  upon  the  ground  are  quickly  rotted,  sending  gases 
into  the  air  and  losing  much  of  what  is  left,  in  the  pounding,  soaking  wash 
of  the  heavy  tropical  rains.  Such  organic  material  as  may  be  present  is 
well  incinerated  when  the  forest  covering  is  killed  and  burned,  as  it  was 
by  the  ancient  Mayas,  and  still  is  by  their  descendants.  Such  a  clearing  will 
yield  a  heavy  crop  for  a  few  seasons,  by  virtue  of  the  fertilizer  in  the  ashes 
and  what  little  is  left  in  the  soil.  Presently  the  yield  must  decline  to  the 
point  where  cultivation  is  no  longer  possible.  A  fresh  clearing  is  made 
and  the  old  one  abandoned.  Step  by  step  the  cultivation  proceeds  farther 
from  the  place  of  beginning.  Whether  the  idle  fields,  forming  an  ever 
widening  border  about  the  great  cities,  came  to  be  hidden  beneath  an 
armor  of  impenetrable  turf  or  completely  ruined  by  sheet  erosion  and 
puddling,  is  immaterial.  The  restoration  of  fertility  by  idleness  has  proved 
a  failure  even  in  temperate  climates.  It  is  not  a  matter  of  one,  or  even 
several,  human  generations,  but  a  process  of  centuries.  The  cities  of  the 
Mayas  were  doomed  by  the  very  system  that  gave  them  birth.  Man's  con- 
quest of  nature  was  an  illusion,  however  brilliant.  Like  China  before  the 
Manchu  invaders,  or  Russia  in  the  face  of  Napoleon,  the  jungle  seemed  to 
yield  and  recede  before  the  Mayas,  only  to  turn  with  deadly,  relentless 
deliberation  and  strangle  them. 

So  much  for  a  striking  case  of  failure  in  the  New  World.  How  about 
the  Old— the  cradle  of  humanity?  Here  there  are  striking  cases  of  apparent 
success,  long  continued,  such  as  eastern  China  and  the  Nile  Valley.  On 

130  THE  EARTH 

the  other  hand  are  many  instances  of  self-destruction  as  dramatic  as  that 
of  the  Mayas — for  example  the  buried  cities  of  the  Sumerian  desert.  Let 
us  examine  both  failure  and  seeming  success;  after  we  have  done  so,  we 
shall  realize  how  closely  they  are  interwoven. 

The  invention  of  flocks  and  herds  of  domestic  animals  enable  man  to 
increase  and  prevail  throughout  the  great  grassy  and  even  the  desert 
interior  of  the  Old  World.  Food  and  wealth  could  be  moved  on  the  hoof. 
A  rough  and  ready  "cowpuncher"  psychology  was  developed  as  a  matter 
of  course,  combining  a  certain  ruthless  capacity  for  quick  action  along  with 
an  aversion  to  sustained  and  methodical  labor,  except  for  women.  Living 
as  these  people  did,  in  a  region  where  water  was  none  too  abundant  and 
pasture  not  always  uniform,  movement  was  necessary.  Normally  this  was 
a  seasonal  migration — a  round  trip  like  that  of  the  buffalo  and  other  wild 
grazing  animals.  But  from  time  to  time  the  combination  of  events  brought 
about  complete  and  extensive  shifts. 

Where  moisture  was  more  abundant,  either  directly  from  rain,  or 
indirectly  through  huge  rivers,  another  invention  took  place.  This  second 
invention  was  the  cultivation  of  certain  nutritious  grasses  with  unusually 
large  fruits — the  cereals.  Probably  not  far  from  the  mouth  of  the  Yangtze 
River  in  southeastern  China  rice  was  domesticated,  while  at  the  eastern 
end  of  the  Mediterranean  wheat  and  barley  were  put  to  similar  use,  both 
in  Irak  (Mesopotamia)  and  Egypt.  Along  with  these  cereals  many  other 
plants,  such  as  beans,  clover,  alfalfa,  onions,  and  the  like  were  grown. 
This  invention  provided  food  cheaply  and  on  a  hitherto  unprecedented 
scale.  Domestic  animals  could  now  be  penned,  using  their  energy  to  make 
flesh  and  milk  instead  of  running  it  off  in  the  continued  movements  for 
grass  and  water.  Other  animals  like  the  cat  and  dog  relieved  man  of  the 
necessity  of  guarding  his  stored  wealth  against  the  raids  of  rats  and 
robbers.  Large  animals  like  the  ox  and  ass  saved  him  the  labor  of  carriage 
and  helped  in  threshing  and  tillage.  The  people  themselves  became 
accustomed  to  methodical  and  prolonged  labor.  They  devised  means  of 
storage  and  transport  and  developed  commerce.  Mechanical  contrivances 
proved  useful  and  were  encouraged.  On  the  other  hand  such  folk  were  not 
celebrated  for  their  aggressiveness  nor  for  an  itching  foot.  As  they  became 
organized  and  accumulated  a  surplus  of  skill  and  energy  they  developed 
great  cities  and  other  public  works,  with  all  adornments. 

The  history  of  early  civilization  can  be  written  largely  in  terms  of 
these  two  great  inventions  in  living — the  pastoral  life  of  the  dry  interior 
and  the  settled  agriculture  of  the  well-watered  regions.  Their  commerce, 
warfare,  and  eventual,  if  imperfect,  combination  make  the  Western 
Europe  of  today.  What  of  their  effects  upon  the  land? 


Wherever  we  turn,  to  Asia,  Europe,  or  Africa,  we  shall  find  the  same 
story  repeated  with  an  almost  mechanical  regularity.  The  net  productive- 
ness of  the  land  has  been  decreased.  Fertility  has  been  consumed  and  soil 
destroyed  at  a  rate  far  in  excess  of  the  capacity  of  either  man  or  nature  to 
replace.  The  glorious  achievements  of  civilization  have  been  builded  on 
borrowed  capital  to  a  scale  undreamed  by  the  most  extravagant  of  mon- 
archs.  And  unlike  the  bonds  which  statesmen  so  blithely  issue  to — and 
against — their  own  people,  an  obligation  has  piled  up  which  cannot  be 
repudiated  by  the  stroke  of  any  man's  pen. 

Uniformly  the  nomads  of  the  interior  have  crowded  their  great  ranges 
to  the  limit.  The  fields  may  look  as  green  as  ever,  until  the  inevitable  drier 
years  come  along.  The  soil  becomes  exposed,  to  be  blown  away  by  wind, 
or  washed  into  great  flooded  rivers  during  the  infrequent,  usually  tor- 
rential rains.  The  cycle  of  erosion  gains  momentum,  at  times  conveying 
wealth  to  the  farmer  downstream  in  the  form  of  rich  black  soil,  but  quite 
as  often  destroying  and  burying  his  means  of  livelihood  beneath  a  coat 
of  sterile  mud. 

The  reduction  of  pasture,  even  with  the  return  of  better  years,  dislocates 
the  scheme  of  things  for  the  owners  of  flocks  and  herds.  Raids,  mass  migra- 
tions, discouraged  and  feeble  attempts  at  agriculture,  or,  rarely,  the 
development  of  irrigation  and  dry  farming  result — and  history  is  made. 

Meanwhile,  in  the  more  densely  settled  regions  of  cereal  farming,  popu- 
lation pressure  demands  every  resource  to  maintain  yield.  So  long  as  rich 
mud  is  brought  downstream  in  thin  layers  at  regular  intervals,  the 
valleys  yield  good  returns  at  the  expense  of  the  continental  interior.  But 
such  imperial  gifts  are  hard  to  control,  increasingly  so  as  occupation  and 
overgrazing  upstream  develop.  In  the  course  of  events  farming  spreads 
from  the  valley  to  the  upland.  The  forests  of  the  upland  are  stripped, 
both  for  their  own  product  and  for  the  sake  of  the  ground  which  they 
occupy.  Growing  cities  need  lumber,  as  well  as  food.  For  a  time  these 
upland  forest  soils  of  the  moister  regions  yield  good  crops,  but  gradually 
they  too  are  exhausted.  Imperceptibly  sheet  erosion  moves  them  into  the 
valleys,  with  only  temporary  value  to  the  latter.  Soon  the  rich  black  valley 
soil  is  overlain  by  pale  and  unproductive  material  from  the  uplands.  The 
latter  may  become  an  abandoned  range  of  gullies,  or  in  rarer  cases  human 
resourcefulness  may  come  to  the  fore,  and  by  costly  engineering  works 
combined  with  agronomic  skill,  defer  the  final  tragedy  of  abandonment. 

Thus  have  we  sketched,  in  broad  strokes  to  be  sure,  the  story  of  man's 
destruction  upon  the  face  of  his  own  Mother  Earth.  The  story  on  the  older 
continents  has  been  a  matter  of  millennia.  In  North  America  it  has  been 
a  matter  of  not  more  than  three  centuries  at  most — generally  a  matter 

132  THE  EARTH 

of  decades.  Mechanical  invention  plus  exuberant  vitality  have  accomplished 
the  conquest  of  a  continent  with  unparalleled  speed,  but  in  doing  so  have 
broken  the  gentle  grip  wherein  nature  holds  and  controls  the  forces 
which  serve  when  restrained,  destroy  when  unleashed. 


What  Makes  the  Weather 


-"-  the  weather,  which  had  been  gray  and  dreary  for  days  and  seemed 
as  if  it  were  going  to  stay  that  way  forever,  with  no  breaks  in  the  clouds 
and  no  indication  of  a  gradual  clearing,  is  now  all  of  a  sudden  clear  and 
sunny  and  crisp,  with  a  strong  northwest  wind  blowing,  and  the  whole 
world  looks  newly  washed  and  newly  painted. 

"It"  has  become  "fine."  Why?  How? 

"Something"  has  cleared  the  air,  you  might  say.  But  what?  You  might 
study  out  the  weather  news  in  the  back  of  your  newspaper,  and  you  would 
get  it  explained  to  you  in  terms  of  barometric  highs  and  lows;  but  just 
why  a  rise  of  barometric  pressure  should  clear  the  air  would  still  leave  you 
puzzled.  The  honest  truth  is  that  the  weather  has  never  been  explained. 
In  school  they  told  you  about  steam  engines  or  electricity  or  even  about 
really  mysterious  things,  such  as  gravitation,  and  they  could  do  it  so 
that  it  made  sense  to  a  boy.  They  told  you  also  about  the  weather,  but 
their  explanations  failed  to  explain,  and  you  knew  it  even  then.  The  lows 
and  highs,  cyclones  and  anti-cyclones,  the  winds  that  blew  around  in  circles 
— all  these  things  were  much  more  puzzling  than  the  weather  itself.  That 
is  why  weather  has  always  made  only  the  dullest  conversation:  there 
simply  was  no  rhyme  nor  reason  to  it. 

But  now  there  is.  A  revolutionary  fresh  view  has  uncovered  the  rhyme 


and  reason  in  the  weather.  Applied  to  your  particular  surprise  of  that 
morning,  it  has  this  to  say: 

Thejiir^vhkh^^  is  .still  warm^  moist, 

and  gray  this  morning ;,  but  it Jias  been  pushed  fifty  or  one  hundred 
to  the  south  and  east  of  where_^pujiyea _and  has  been  replaced  by  aj 
of  "cold,  clear,  dry  air  coming  from  the  north  or  west.  It  is  as  simple  as  that; 
there  is  no  mysterious  "It"  in  it;  just  plain  physical  sense.  It  is  called  Air 
Mass  Analysis. 

It  is  based  upon  the  researches  and  experiments  of  a. physicist  named 
YilhdlII_Bigrkncs,  of_Nprway,  and  though  in  this  particular  case  it 
seems  almostT  childishly  simple,  it  is  Norway's  greatest  contribution  to 
world  culture  since  Ibsen.  Or  perhaps  because  it  is  simple — the  rare 
example  of  a  science  which  in  becoming  more  sophisticated  also  becomes 
more  common  sense  and  easier  to  understand.  It  is  so  new  that  it  hasn't 
yet  reached  the  newspapers,  nor  the  high  school  curricula,  much  less  the 
common  knowledge  of  the  public  in  general.  But  the  weather  bureaus 
of  the  airlines  have  worked  by  it  for  years,  and  pilots  have  to  learn  it. 
It  is  indispensable  both  in  commercial  flying  and  in  air  war;  we  could  fly 
without  gasoline,  without  aluminum,  perhaps  without  radio,  but  we  could 
never  do  without  Bjerknes's  Air  Mass  Analysis. 

You  might  inquire  next  whereThat  morning's  new  air  came  from,  and 
just  how  it  got  to  be  cold,  dry,  and  clear.  And  there  you  get  close  to  the 
heart  of  the  new  weather  science,  where  meteorology  turns  into  honest, 
common-sense  geography. 

That  air  has  come  from  Canada,  where  it  has  been  quite  literally  air- 
conditioned.  Not  all  parts  ~bf  the  world  have  the  power  to  condition  air, 
but  Canada  has.  Especially  in  the  fall  and  winter  and  early  spring,  the 
northern  part  of  this  continent  becomes^  an  almost  perfectly  designed 
mechanical  refrigeratoiTTrie  "Rocky  Mountains  in  the  west  keep  currents 
of  new  air  from  flowing  intolBe"  regBru  And  for  weeks  the  air  lies  still. 
The  cool  ground,  much  of  it  snow-covered;  the  ice  of  the  frozen  lakes; 
plus  the  perennial  stored-up  coldness  of  Hudson's  Bay — all  cool  the  layer 
of  air  immediately  above  them.  This  means  a  stabilizing  and  calming  of 
the  whole  atmosphere  all  the  way  up;  for  cool  air  is  heavy^  and  with  a 
heavy  layer  bottommost,  there  is  none_of  that  upflowing  of  air,  that  up- 
welling  of  moisture-laden  heat  into  the  cooler,Tiigh  altitude  which  is  the 
mechanism  that  makes  cloud siTHus  there  may  be  some  low  ground  fogs 
there,  but  above  them  the  long  nights  of  those  northern  latitudes  are  clear 
and  starry,  wide  open  toward  the  black  infinite  spaces  of  the  universe; 
and  into  that  black  infinity  the  air  gradually  radiates  whatever  warmth  it 
may  contain  from  its  previous  sojourns  over  other  parts  of  the  world* 

134  THE  EARTH 

The  result,  after  weeks  of  stagnation,  is  a  huge  mass  of  air  that  is  uni- 
formly ice-cold,  dry,  and  clear.  It  stretches  from  the  Rocky  Mountains 
in  the  west  to  Labrador  in  the  east,  from  the  ice  wastes  of  the  Arctic  to  the 
prairies  of  Minnesota  and  North  Dakota;  and — the  third  dimension  is  the 
most  important — it  is  ice-cold  from  the  ground  all  the  way  up  to  the 
stratosphere.  It  is,  in  short,  a  veritable  glacier  of  air. 

That  is  an  air  mass.  In  the  jargon  of  air-faring  men,  a  mass  of  JPolar 
Canadian' ain" 

When  a  wave  of  good,  fresh  Polar  Canadian  air  sweeps  southward  into 
the  United  States — it  happens  almost  rhythmically  every  few  days — you 
don't  need  a  barometer  to  tell  you  so.  There  is  nothing  subtle,  theoretical, 
or  scientific  about  it.  You  can  see  and  feel  the  air  itself  and  even  hear  it.  It 
comes  surging  out  of  a  blue-green  sky  across  the  Dakptas,  shaking  the 
hangar  doors,  whistling  in  the  grassTputting  those  red-checkered  thick 
woolen  jackets  on  the  men,  and  lighting  the  stoves  in  the  houses.  It  flows 
southward  down  the  Mississippi  Valley  as  a  cold  wave  in  winter,  or  as 
relief  from  a  heat  wave  in  summer,  blowing  as  a  northwest  wind  with 
small  white  hurrying  clouds  in  it.  In  winter  it  may  sweep  southward  as 
far  as  Tennessee  and  the  Carolinas,  bringing  frosts  with  brilliantly^clear 
skies,  making  the  darkies  shiver  in  their  drafty  cabins,  and  producing  a 
wave  of  deaths  by  pneumonia.  Sometimes  it  even  reaches  the  Texas  Gulf 
Coast;  then  it  is  locally  called  a  norther,  and  the  cows  at  night  crowd  for 
warmth  around  the  gas  flares  in  the  oil  fields.  A  duck  hunter  dies  of 
exposure  in  the  coastal  swamps.  A  lively  outbreak  of  Polar  Canadian  air 
may  reach  down  into  Florida,  damage  the  orange  crops,  and  embarrass 
local  Chambers  of  Commerce.  And  deep  outbreaks  have  been  observed  to 
drive  all  the  way  down  to  Central  America,  where  they  are  feared  as  a 
fierce  wind  called  the  Tehuantepecer. 

Polar  Canadian  is  only  one  of  many  sorts  of  air.  To  put  it  in  the 
unprecise  language  of  the  layman,  the  great  Norwegian  discovery  is  that 
air  must  always  be  of  some  distinct  type:  that  it  is  never  simply  air  but 
always  conditioned  and  flavored.  What  we  call  weather  is  caused  by 
gigantic  waves  in  the  air  ocean  which  flood  whole  countries  and  conti- 
nents for  days  at  a  stretch  with  one  sort  of  air  or  another.  And  there  is 
nothing  theoretical  about  any  of  these  various  sorts  of  air. 

Each  kind  is  easily  seen  and  felt  and  sniffed,  and  is,  in  fact,  fairly 
familiar  even  to  the  city  dweller,  although  he  may  not  realize  it.  Each  has 
its  own  peculiar  characteristics,  its  own  warmth  or  coolness,  dampness  or 
dryness,  milkiness  or  clearness.  Each  has  its  own  quality  of  light.  In  each, 
smoke  behaves  differently  as  it  pours  from  the  chimneys:  in  some  kinds 
of  air  it  creeps  lazily,  in  some  it  bubbles  away,  in  some  it  floats  in  layers- 


That  is  largely  why  the  connoisseur  can  distinguish  different  types  of  air 
by  smell. 

Each  type  of  air  combines  those  qualities  into  an  "atmosphere"  of  its 
own.  Each  makes  an  entirely  different  sort  of  day.  In  fact,  what  sort  of  day 
it  is — raw,  oppressive,  balmy,  dull,  a  "spring"  day — depends  almost  entirely 
upon  the  sort  of  air  that  lies  over  your  particular  section  of  the  country  at 
that  particular  time. 

And  if  you  tried  to  describe  the  day  in  the  old-fashioned  terms — wind 
direction  and  velocity,  humidity,  state  of  the  sky — you  could  never  quite 
express  its  particular  weather;  but  you  can  by  naming  the  sort  of  air.  An 
airplane  pilot,  once  he  is  trained  in  the  new  weather  thinking,  can  get 
quite  impatient  with  the  attempts  of  novelists,  for  instance,  to  describe 
weather.  "Why  don't  you  say  it  was  Polar  Canadian  air  and  get  on  with 
your  story?" 

And  if  you  are  a  connoisseur  of  airs  just  about  the  first  thing  you  will 
note  every  morning  is  something  like,  "Ah,  Caribbean  air  to-day";  or  if 
you  are  really  a  judge  you  can  make  statements  as  detailed  as,  "Saskatch- 
ewan air,  slightly  flavored  by  the  Great  Lakes." 

For  just  as  wines  do,  the  airs  take  their  names  and  their  flavors  from 
the  regions  where  they  have  matured.  Of  the  seven  airs  that  make  up  the 
American  weather,  one  is  quite  rare  and  somewhat  mysterious.  It  is 
known  by  the  peculiarly  wine-like  name  of  Sec  Superieur.  It  is  believed 
to  be  of  tropical  origin,  but  it  comes  to  this  continent  after  spending  weeks 
in  the  stratosphere  somewhere  above  the  Galapagos  Islands.  It  is  usually 
found  only  high  aloft,  and  interests  pilots  more  than  farmers.  But  once 
in  a  while  a  tongue  of  it  reaches  the  ground  as  hot,  extremely  dry,  very 
clear  weather;  and  wherever  it  licks  there  is  a  drought. 

The  other  six  airs  all  come  from  perfectly  earthly  places,  though  far- 
away ones.  The  easiest  to  recognize,  the  liveliest,  is  Polar  Canadian.  Its 
opposite  number  in  the  American  sky  is  Trnpicd  JGlilf  ^r  Trnpirrrf 
AtlagtJ£.(<Jaiirr-the  steamy,  warm  air  of  the  Eastern  and  MidvE&§j£rn 
summer^  the  kind  Hiaf "comes  alHTsotfftTfl^  starts  people  to 

taflungabout  heat  and  humidity,  the  kind  that  is  sometimes  so  steamy  that 
it  leaves  you  in  doubt  as  to  whether  the  sky  means  to  be  blue  or  overcast. 
This  air  is  brewed  of  hot  sun  and  warm  sea  water  in  the  Caribbean 
region.  The  mechanism  that  does  the  air  conditioning  in  this  case  is 
mostly  the  daily  afternoon  thunderstorm  which  carries  moisture  and  heat 
high  aloft  in  it. 

Not  quite  SQ  obvious  is  the  origin  of  the  moist,  silvery,  coolicbaununer^ 
cool-in-winter  air  that  dominates  the  wcathciL^-Sga.tdf  •  It  jscallej  Polar 
PaciBcpand  it  is  a  trick  product.  Its  basic  characteristics  have  been 

136  THE  EARTH 

acquired  over  Siberia  and  it  is  cold  and  dry;  but  on  its  way  across  the 
Pacific  its  lower  five  to  ten  thousand  feet  have  been  warmed  up  and 
moistened.  Sometimes  such  air  comes  straight  across,  reaching  land  in  a 
couple  of  days.  Sometimes  it  hangs  over  the  water  for  a  week,  and  it 
takes  a  good  weatherman  to  predict  just  what  sort  of  weather  it  will 

Its  counterpart  is  a  flavor  known  as  Tropical  Pacific.  That  is  the  air  they 
sell  to  tourists  in  Southern  California.  It  is  really  just  plain  South  Seas 
air,  though  the  story  here  too  is  not  as  clear-cut  as  it  might  be. 

A  clear-cut  type  is  Polar  Atlaruic^ir.  It  sometimes  blows  down  the  New 
England  coast  as  a  nor'easter,  cold,  rainy,  with  low  clouds.  It  is  simply 
a  chunk  of  the  Grand  Banks  off  Newfoundland  gone  traveling,  and  you 
can  almost  smell  the  sea. 

And  one  air  that  every  tourist  notices  in  the  Southwest  is  Tropical  Con-' 
tinental.  Its  source  region  is  the  deserts  of  Arizona  and  Mexico.  It  is  dry 
and  hot  and  licks  up  moisture  so  greedily  that  it  makes  water  feel  on  youf 
skin  as  chilly  as  if  it  were  gasoline.  It  is  not  an  important  one  for  America, 
though  its  European  counterpart,  Saharan  air,  is  important  for  Europe. 
Oklahoma,  Colorado,  and  Kansas  are  as  far  as  it  ever  gets;  but  even  so, 
a  few  extra  outbreaks  of  it  per  year,  and  we  have  a  dust  bowl. 


The  air  mass  idea  is  simple.  As  great  ideas  often  do,  the  air  mass  idea 
makes  you  feel  that  you  have  known  it  right  along.  And  in  a  vague  way, 
you  have.  Take,  for  example,  that  half-brag,  half-complaint  of  the  Texans 
that  there  is  nothing  between  Texas  and  the  North  Pole  to  keep  out  those 
northers  but  a  barbed  wire  fence:  it  contains  the  kernel  of  the  whole  idea — 
the  invading  air  mass — but  only  in  a  fooling  way.  Or  take  the  manner  in 
which  the  Mediterranean  people  have  always  given  definite  names  to  cer- 
tain winds  (boreas,  sirocco,  mistral)  that  blow  hot  or  cold,  dry  or  moist, 
across  their  roofs.  They  are  names,  however,  without  the  larger  view.  In 
creative  literature  such  things  as  a  cold  front  passage — the  sudden  arrival 
of  a  cold  air  mass — have  been  described  several  times  quite  accurately, 
but  always  as  a  local  spectacle,  with  the  key  thought  missing. 

Actually  it  took  genius  to  see  it.  For  air  is  a  mercurial  fluid,  bubbly, 
changeable;  it  is  as  full  of  hidden  energies  as  dynamite;  it  can  assume  the 
most  unexpected  appearances.  There  are  days,  to  be  sure,  when  the  air 
virtually  advertises  its  origin.  Offhand,  you  might  say  that  on  perhaps  half 
the  days  of  the  year  it  does.  But  there  are  also  days  when  it$  appearance  is 
altogether  misleading. 

Take,   for   example,   the   amazing   metamorphosis    that  happens   to 


Tropical  Gulf  air  when  it  flows  northward  across  the  United  States  in 
winter.  It  starts  out  from  among  the  Islands  looking  blue  and  sunny  and 
like  an  everlasting  summer  afternoon.  When  it  arrives  over  the  northern 
United  States  that  same  air  appears  as  a  dark-gray  shapeless,  drizzling  over- 
cast, and  in  the  office  buildings  of  New  York  and  Chicago  the  electric 
lights  are  on  throughout  what  is  considered  a  shivery  winter  day.  It  is 
still  the  same  air;  if  we  could  mix  a  pink  dye  into  the  air,  as  geographers 
sometimes  mix  dyes  into  rivers  to  trace  the  flow  of  water,  a  cloud  of  pink 
air  would  have  traveled  from  Trinidad  to  New  York.  It  has  hardly 
changed  at  all  its  actual  contents  of  heat  and  water;  but  as  far  as  its 
appearance  and  its  feel  are  concerned — its  "weather"  value — a  few  days 
of  northward  traveling  have  reversed  it  almost  into  a  photographic  nega- 
tive of  itself. 

What  happens  in  this  particular  case — and  it  accounts  for  half  our  winter 
days — is  simply  that  the  cool  ground  of  the  wintry  continent  chills  this 
moist,  warm  air  mass — chills  it  just  a  little,  not  enough  to  change  its 
fundamental  character,  and  not  all  the  way  up  into  its  upper  levels,  but  in 
its  bottommost  Ir.yer  and  that  only  just  enough  to  make  it  condense  out 
some  of  its  abundant  moisture  in  the  form  of  visible  clouds;  it  is  quite 
similar  to  the  effect  of  a  cold  window  pane  on  the  air  of  a  well-heated, 
comfortable  room — there  is  wetness  and  cooling  right  at  the  window,  but 
the  bulk  of  the  room's  air  is  not  affected. 

Perhaps  the  oddest  example  of  this  is  the  trick  by  which  Polar  Pacific 
air,  striking  the  United  States  at  Seattle,  cool  and  moist,  arrives  in  eastern 
Montana  and  the  Dakotas  as  a  chinook,  a  hot,  dry,  snow-melting  wind. 

As  Polar  Pacific  air  flows  up  the  slopes  of  the  Sierras  and  the  Cascades 
it  is  lifted  ten  thousand  feet  into  the  thinner  air  of  higher  altitude.  By  one 
law  of  physics  the  lifting  should  chill  the  air  through  release  of  pressure. 
If  you  have  ever  bled  excess  pressure  out  of  your  tires  you  know  this  cool- 
ing by  release  of  pressure — you  know  how  ice-cold  the  air  comes  hissing 
out.  But  in  this  case,  by  a  different  law  of  physics,  Polar  Pacific  reacts  by 
cooling  only  moderately;  then  it  starts  condensing  out  its  moisture  and 
thereby  protecting  its  warmth;  hence  the  tremendous  snowfalls  of  the 
sierras,  the  giant  redwoods,  the  streams  that  irrigate  California  ranches. 

Once  across  the  Cascades  and  the  Sierras,  the  air  flows  down  the  eastern 
slopes.  In  descending  it  comes  under  pressure  and  therefore  heats  up,  just 
as  air  heats  up  in  a  tire  pump.  Warmed,  the  air  increases  its  capacity  to 
hold  moisture;  it  becomes  relatively  drier — thus  this  air  sucks  back  its 
own  clouds  into  invisible  form.  When  it  arrives  over  the  Columbia  Basin, 
or  the  country  round  Reno,  or  Owens  Valley,  it  is  regular  desert  air — 
warm,  very  clear,  and  very  dry.  That  is  why  the  western  deserts  are 

138  THE  EARTH 

where  they  are.  Flowing  on  eastward,  it  comes  against  another  hump, 
the  Continental  Divide  and  the  Rockies.  Here  the  whole  process  repeats 
itself.  Again  the  air  is  lifted  and  should  become  ice-cold;  again  it  merely 
cools  moderately,  clouds  up,  and  drops  its  remaining  moisture  to  protect 
its  warmth;  hence  the  lush  greenery  of  Coeur  d'Alene,  the  pine  forests 
of  New  Mexico.  Finally,  as  the  air  flows  down  the  eastern  slope  of  the 
Rockies,  compression  heats  it  once  more,  as  in  the  bicycle  pump.  Twice 
on  the  way  up  it  has  dropped  moisture  and  thus  failed  to  cool;  twice 
on  the  way  down  it  has  been  heated :  it  is  now  extremely  dry,  and  twenty 
degrees  warmer  than  it  was  at  Seattle.  That  is  the  chinook,  a  wind 
manufactured  of  exactly  the  sort  of  principles  that  work  in  air-condition- 
ing machinery,  and  a  good  example  of  the  trickery  of  air  masses.  But  it 
is  still  a  simple  thing;  it  is  still  one  actual  physically  identical  mass  of  air 
that  you  are  following.  It  you  had  put  pink  smoke  into  it  at  Seattle,  pink 
smoke  would  have  arrived  in  South  Dakota. 

That  is  how  the  air  mass  concept  explains  all  sorts  of  weather  detail: 
the  various  kinds  of  rain — showery  or  steady;  the  many  types  of  cloud — 
low  or  high,  solid  or  broken,  layered  or  towering;  thunderstorms;  fog. 
An  air  mass,  thus-and-thus  conditioned,  will  react  differently  as  it  flows 
over  the  dry  plains,  the  freshly  plowed  cotton  fields,  the  cool  lakes,  the 
hot  pavements,  the  Rocky  Mountains  of  the  United  States. 

An  airplane  pilot's  weather  sense  consists  largely  of  guessing  the  exact 
manner  in  which  a  given  sort  of  air  will  behave  along  his  route.  Tropical 
Gulf  in  summer  over  Alabama?  Better  not  get  caught  in  the  middle  after- 
noon with  a  low  fuel  reserve.  We  shall  have  to  detour  around  many 
thunderstorms.  The  details  are  as  multifarious  as  geography  itself,  but 
much  of  it  has  by  now  been  put  into  the  manuals,  and  the  pilot  memorizes 
such  items  as  these: 

Canadian  air  that  passes  over  the  Great  Lakes  in  winter  is  moistened 
and  warmed  in  its  lower  layers  and  becomes  highly  unstable.  When  such 
air  hits  the  rolling  country  of  western  Pennsylvania  and  New  York  and 
the  ridges  of  the  Appalachians  the  hills  have  a  sort  of  "trigger  action" 
and  cause  snow  flurries  or  rain  squalls  with  very  low  ceilings  and  visibility. 

In  summer,  Canadian  air  that  flows  into  New  England,  dried,  without 
passing  over  the  Great  Lakes,  will  be  extremely  clear  and  extremely 

Tropical  Gulf  over  the  South  forms  patchy  ground  fog  just  before 
sunrise  that  will  persist  for  two  or  three  hours. 

As  Polar  Pacific  air  moves  southward  along  the  Pacific  Coast  it  forms 
a  layer  of  "high  fog." 


In  Colorado  and  Nebraska  fresh  arriving  Canadian  air  frequently  shows 
as  a  dust  storm. 

Given  two  types  of  country  underneath,  one  kind  of  air  can  produce 
two  sorts  oi  weather  only  a  few  miles  apart.  Tropical  Atlantic  air,  for 
instance,  appears  over  the  hills  of  New  England  as  hot  and  summery 
weather,  slightly  hazy,  inclined  toward  afternoon  thunderstorms.  A  few 
miles  of?  the  coast  the  same  air  appears  as  low  banks  of  fog.  That  is 
because  the  granite  and  the  woods  are  warmed  all  through,  and  actually 
a  little  warmer  than  Tropical  Gulf  air  itself,  at  least  during  the  day; 
while  the  ocean  is  much  colder  than  the  air,  and  cools  it. 

Again,  one  kind  of  country  can  have  opposite  effects  on  two  different 
types  of  air.  For  example,  the  farms  of  the  Middle  West  in  the  spring 
when  the  frost  is  just  out  of  the  ground:  that  sort  of  country  feels  cool 
to  Tropical  Gulf  air  that  has  flowed  up  the  Mississippi  Valley.  The  bottom 
layers  of  that  warm  moist  air  are  chilled  and  thus  the  whole  air  mass  is 
stabilized.  It  will  stay  nicely  in  layers;  the  clouds  will  form  a  flat,  level 
overcast;  smoke  will  spread  and  hover  as  a  pall.  But  to  a  mass  of  freshly 
broken-out  Canadian  air  that  sort  of  country  feels  warm.  The  air  in 
immediate  contact  with  the  ground  is  warmed,  and  the  whole  mass 
becomes  bottom-light  and  unstable. 

And  that  means  action:  a  commotion  much  like  the  boiling  of  water 
on  a  huge  scale  and  in  slow  motion.  The  warmed  air  floats  away  upward 
to  the  colder  air  aloft,  forming  bubbles  of  rising  air,  hundreds  of  feet 
in  diameter,  that  are  really  hot-air  balloons  without  a  skin. 

Those  rising  chunks  of  air  are  felt  by  fliers  as  bumps.  When  the  ship 
flies  into  one  it  gets  an  upward  jolt;  when  it  flies  out  again  it  gets  a  down- 
ward jolt.  They  are  what  makes  it  possible  to  fly  a  glider,  even  over  flat 
country;  all  you  have  to  do  is  to  find  one  of  those  bubbles,  stay  in  it  by 
circling  in  a  tight  turn,  and  let  it  carry  you  aloft. 

The  clear  air,  the  tremendous  visibility  of  such  a  day  is  itself  the  result 
of  instability:  the  rising  bubbles  carry  away  the  dust,  the  haze,  the  indus- 
trial smoke.  The  air  is  always  roughest  on  one  of  those  crisp,  clear,  newly 
washed  days.  If  the  rising  air  gets  high  enough  it  makes  cumulus  clouds, 
those  characteristic,  towering,  puffy  good-weather  clouds.  That  sort  of 
cloud  is  nothing  but  a  puff  of  upward  wind  become  visible.  The  rise 
has  cooled  the  air  and  made  its  water  vapor  visible.  Soaring  pilots  seek 
to  get  underneath  a  cumulus  cloud — there  is  sure  to  be  a  lively  upflow 
there.  Sometimes,  in  really  unstable  air,  the  rising  of  the  air  reaches 
hurricane  velocities.  We  call  that  a  thunderstorm,  but  the  lightning  and 
thunder  are  only  by-products  of  the  thing.  The  thing  itself  is  simply  a 
vicious,  explosive  upsurging  of  air:  the  wind  in  thunderstorms  blows 

140  THE  EARTH 

sixty  to  one  hundred  miles  per  hour — straight  up!  The  most  daring  of 
soaring  pilots  have  flown  into  thunderstorms  and  have  been  sucked  up 
almost  to  the  stratosphere. 

The  weatherman,  unlike  the  pilot,  need  not  guess.  He  has  got  a  slide 
rule;  he  has  got  the  laws  of  gases,  Charles's  Law,  Boyle's  Law,  Buys 
Ballot's  Law  at  his  fingertips.  He  has  studied  thermodynamics,  and  he 
has  got  a  new  device  that  is  the  biggest  thing  in  weather  science  since 
Torricelli  invented  the  barometer — the  radio  sonde  with  which  he  can 
take  soundings  of  the  upper  air,  find  out  just  how  moisture  and  tempera- 
ture conditions  are  aloft,  just  how  stable  or  unstable  the  air  will  be,  at 
what  level  the  clouds  will  form,  and  of  what  type  they  will  be. 

Radio  sondes  go  up  in  the  dead  of  night  from  a  dozen  airports  all  over 
the  continent.  The  radio  sonde  looks  like  a  box  of  candy,  being  a  small 
carton  wrapped  in  tinfoil;  but  it  is  actually  a  radio  transmitter  coupled 
to  a  thermometer  and  a  moisture-meter.  It  is  hung  on  a  small  parachute 
which  is  hitched  to  a  balloon.  It  takes  perhaps  an  hour  for  the  balloon 
to  reach  the  stratosphere,  and  all  the  time  it  signals  its  own  readings  in 
a  strange,  quacky  voice,  half  Donald  Duck,  half  voice  from  the  beyond. 
Then  it  stops.  You  know  that  the  balloon  has  burst,  the  parachute  is 
letting  the  instrument  down  gently. 

The  next  morning  some  farm  boy  finds  the  shiny  thing  in  a  field,  with 
a  notice  attached  offering  a  reward  for  mailing  it  back  to  the  weather 

Also  the  next  morning  a  man  in  Los  Angeles  paces  up  and  down  his 
office,  scanning  the  wall  where  last  night's  upper-air  soundings  are  tacked 
up.  Emitting  heavy  cigar  smoke  and  not  even  looking  out  of  the  window, 
he  dictates  a  weather  forecast  for  the  transcontinental  airway  as  far  east 
as  Salt  Lake  City,  a  forecast  that  goes  into  such  detail  that  you  sometimes 
think  he  is  trying  to  show  off. 


With  the  air  mass  idea  as  a  key,  you  can  make  more  sense  out  of  the 
weather  than  the  professional  weatherman  could  before  Bjerknes;  and 
even  if  you  don't  understand  Boyle's  Law  and  all  the  intricate  physics 
of  the  atmosphere,  you  can  do  a  quite  respectable  job  of  forecasting. 

It  goes  like  this :  suppose  you  are  deep  in  Caribbean  air.  You  will  have 
"air  mass  weather":  a  whole  series  of  days  of  the  typical  sort  that  goes 
with  that  particular  type  of  air  when  it  overlies  your  particular  section  of 
the  country  in  that  particular  season.  There  will  be  all  sorts  of  minor 
changes;  there  will  be  a  daily  cycle  of  weather,  clouds,  perhaps  thunder- 
storms, or  showers;  but  essentially  the  weather  will  be  the  same  day  aftet 


day.  Any  real  change  in  weather  can  come  only  as  an  incursion  of  a  new 
air  mass — probably  Polar  Canadian. 

And  when  that  air  mass  comes  you  will  know  it.  New  air  rarely  comes 
gently,  gradually,  by  imperceptible  degrees;  almost  always  the  new  air 
mass  advances  into  the  old  one  with  a  clear-cut,  sharply  defined  forward 
front.  Where  two  air  masses  adjoin  each  other  you  may  in  half  an  hour's 
driving — in  five  minutes'  flying — change  your  entire  weather,  travel 
from  moist,  muggy,  cloudy  weather  into  clear,  cool,  sunny  weather. 
That  clear-cut  boundary  is  exactly  what  makes  an  air  mass  a  distinct 
entity  which  you  can  plot  on  a  map  and  say,  "Here  it  begins;  here  it 
ends";  these  sharp  boundaries  of  the  air  masses  are  called  "fronts"  and 
are  a  discovery  as  important  as  the  air  mass  itself. 

You  are  watching,  then,  for  a  "cold  front,"  the  forward  edge  of  an 
advancing  mass  of  cold  air.  You  will  get  almost  no  advance  warning. 
You  will  see  the  cold  air  mass  only  when  it  is  practically  upon  you.  But 
you  know  that  sooner  or  later  it  must  come,  and  that  it  will  come  from 
the  northwest.  Thus,  an  occasional  long-distance  call  will  be  enough- 
Suppose  you  are  in  Pittsburgh,  with  a  moist,  warm  southwest  wind:  the 
bare  news  that  Chicago  has  a  northerly  wind  might  be  enough  of  a  clue.. 
If  you  knew  also  that  Chicago  was  twenty  degrees  cooler  you  would  be 
certain  that  a  cold  air  mass  had  swamped  Chicago  and  was  now  presum- 
ably on  its  way  to  Pittsburgh,  traveling  presumably  at  something  like 
30  m.p.h.  You  could  guess  the  time  of  arrival  of  its  forward  front  within 
a  few  hours.  That  is  why  the  most  innocent  weather  reports  are  now 
so  secret;  why  the  British  censor  suppresses  snow  flurries  in  Scotland;, 
why  a  submarine  in  the  Atlantic  would  love  to  know  merely  the  wind 
direction  and  temperature  at,  say,  Columbus,  Ohio;  why  the  Gestapo* 
had  that  weather  station  in  Greenland. 

Knowing  that  a  cold  front  is  coming,  you  know  what  kind  of  weather 
to  expect;  though  some  cold  fronts  are  extremely  fierce,  and  others  quite 
gentle  (noticeable  only  if  you  watch  for  them),  the  type  is  always  the 
same.  It  is  all  in  the  book — Bjerknes  described  it  and  even  drew  pictures 
of  it.  It  was  the  advance  of  such  a  cold  front  which  occurred  while  you 
slept  that  night  before  you  awoke  to  find  the  world  fresh  and  newly 

Cold  air  is  heavy;  as  polar  air  plows  into  a  region  occupied  by  tropical 
air  it  underruns;  it  gets  underneath  the  warm  air  and  lifts  it  up  even 
as  it  pushes  it  back.  A  cold  front  acts  physically  like  a  cowcatcher. 

Seen  from  the  ground,  the  sequence  of  events  is  this:  an  hour  or  two- 
before  the  cold  front  arrives  the  clouds  in  the  sky  become  confused,, 
somewhat  like  a  herd  of  cattle  that  smells  the  coyotes;  but  you  observe- 

142  THE  EARTH 

that  by  intuition  rather  than  by  measurable  signs.  Apart  from  that,  there 
are  no  advance  signs.  The  wind  will  be  southerly  to  the  last,  and  the  air 
warm  and  moist. 

Big  cumulus  clouds  build  up  all  around,  some  of  them  with  dark 
bases,  showers,  and  in  summer  thunder  and  lightning — that  is  the  warm 
moist  air  going  aloft.  A  dark  bank  of  solid  cloud  appears  in  the  north- 
west, and  though  the  wind  is  still  southerly,  this  bank  keeps  building  up 
and  coming  nearer:  it  is  the  actual  forward  edge  of  the  advancing  cold 
air.  When  it  arrives  there  is  a  cloudburst.  Then  the  cold  air  comes  sweep- 
ing in  from  the  northwest  with  vicious  gusts.  This  is  the  squall  that  cap- 
sizes sailboats  and  uproots  trees,  flattens  forests  and  unroofs  houses. 

The  whole  commotion  probably  is  over  in  half  an  hour.  The  wind  eases 
up,  though  it  is  still  cool  and  northwesterly,  the  rain  ceases,  the  clouds 
break  and  new  sky  shows:  the  front  has  passed,  the  cold  air  mass  has 

The  weatherman  can  calculate  these  things  too.  He  has  watched  and 
sounded  out  each  of  the  two  air  masses  for  days  or  even  weeks,  ever 
since  it  moved  into  his  ken  somewhere  on  the  outskirts  of  the  American 
world.  Thus  an  airline  weatherman  may  look  at  a  temperature-moisture 
graph  and  say,  "This  is  dynamite.  This  air  will  be  stable  enough  as  long 
as  it  isn't  disturbed.  But  wait  till  some  cold  air  gets  underneath  this  and 
starts  lifting  it.  This  stuff  is  going  to  go  crazy." 

In  making  your  own  guess  you  would  take  the  same  chance  that  the 
weatherman  takes  every  morning — that  you  might  be  right  and  yet  get 
an  error  chalked  up  against  you.  Suppose  the  Chicago  weatherman, 
seeing  a  cold  front  approach,  forecasts  thunderstorms.  One  thunderstorm 
passes  north  of  the  city,  disturbing  the  30,000  inhabitants  of  Waukegan. 
Another  big  one  passes  south  of  Chicago,  across  farms  just  south  of  Ham- 
mond, Ind.,  affecting  another  30,000  people.  None  happens  to  hit  Chicago 
itself,  with  its  3  million  people.  On  a  per  capita  basis,  the  weatherman  was 
98  per  cent  wrong!  Actually  he  was  right. 

Now  you  are  in  the  cold  air  mass,  and  you  can  reasonably  expect  "air 
mass  weather"  for  a  while  rather  than  "frontal"  weather;  />.,  a  whole 
series  of  whatever  sort  of  day  goes  with  Canadian  air  in  your  particular 
section  of  the  country  at  that  particular  season. 

Any  real  change  in  the  weather  nous  can  again  come  only  with  an 
incursion  of  a  new  and  different  air  mass— and  now  that  will  probably 
mean  tropical  maritime  air  of  the  Gulf  kind.  To  forecast  that  invasion 
is  no  trick  at  all:  you  can  see  the  forward  front  of  the  warm  air  mass 
in  the  sky  several  days  before  it  sweeps  in  on  the  ground.  Warm  air  is 
light.  As  Caribbean  air  advances  into  a  region  occupied  by  Canadian  air 


it  produces  a  pattern  that  is  the  exact  opposite  of  the  cold  front.  The 
warm  front  overhangs  forward,  overruns  the  cold  air;  the  warm  air  mass 
may  appear  high  above  Boston  when  at  ground  level  it  is  just  invading 
Richmond,  Va. 

Again  the  sequence  of  events  is  predictable — Bjerknes  drew  the  picture. 
It  is  the  approaching  warm  front  that  makes  for  "bad"  weather,  for  rain 
of  the  steady,  rather  than  the  showery  kind,  for  low  ceilings. 

Consider  a  warm  front  on  the  morning  when  its  foot  is  near  Rich- 
mond and  its  top  over  Boston.  Boston  that  morning  sees  streaks  of  cirrus 
in  its  sky — "mares'  tails,"  the  white,  feathery,  diaphanous  cloud  arranged 
in  filaments  and  bands,  that  is  so  unsubstantial  that  the  sun  shines  clear 
through  it  and  you  are  hardly  conscious  of  it  as  a  cloud — and  actually  it 
doesn't  consist  of  water  droplets,  as  do  most  clouds,  but  of  ice  crystals. 
New  Haven  the  same  morning  has  the  same  kind  of  cloud,  but  slightly 
thicker,  more  nearly  as  a  solid,  milky  layer.  New  York  that  same  morning 
sees  the  warm  air  as  a  gray  solid  overcast  at  8,000  feet.  Philadelphia  has 
the  same  sort  of  cloud  at  5,000,  with  steady  rain.  Washington  has  1,500 
feet,  rain.  Quantico  and  Richmond  report  fog,  and  all  airplanes  are 
grounded.  Raleigh,  N.C.,  has  clearing  weather,  the  wind  has  shifted  that 
morning  to  the  southwest,  and  it  is  getting  hot  and  humid  there.  Raleigh 
would  be  definitely  behind  the  front,  well  in  the  warm  air  mass  itself. 

By  nightfall  Boston  has  the  weather  that  was  New  Haven's  in  the 
morning.  The  moon,  seen  through  a  milky  sheet  of  cirrus  clouds,  has  a 
halo:  "There  is  going  to  be  rain."  New  Haven  that  night  has  New  York's 
weather  of  that  morning;  New  York  has  Philadelphia's;  and  so  on  down 
the  line — the  whole  front  has  advanced  one  hundred  miles.  In  fore- 
casting the  weather  for  Boston  it  is  safe  to  guess  that  Boston  will  get  in 
succession  New  Haven  weather,  New  York  weather,  Philadelphia, 
Washington,  Richmond  weather — and  finally  Raleigh  weather — in  a 
sequence  that  should  take  two  or  three  days:  steady  lowering  clouds, 
rainy  periods,  some  fog — followed  finally  by  a  wind  shift  to  the  southwest, 
and  rapid  breaking  of  clouds,  and  much  warmer,  very  humid  weather. 

And  then  the  cycle  begins  all  over.  You  are  then  deep  in  Caribbean 
air  again.  You  will  have  Caribbean  air  mass  weather,  and  your  weather  eye 
had  better  be  cocked  northwest  to  watch  for  the  first  signs  of  polar  air. 


There  is  a  rhythm,  then,  in  the  weather,  or  at  least  a  sort  of  rhyme, 
a  repetitive  sequence.  All  those  folk  rules  that  attribute  weather  changes 
to  the  phases  of  the  moon,  or  to  some  other  simple  periodicity  ("If  the 
weather  is  O.K.  on  Friday,  it  is  sure  to  rain  over  the  week-end")  are 

144  THE  EARTH 

not  so  far  from  the  mark  after  all.  The  rhythm  does  not  work  in  terms 
of  rain  or  shine;  but  it  does  work  in  terms  of  air  masses;  and  thus, 
indirectly  and  loosely,  through  the  tricky  physics  of  the  air,  it  governs 
also  the  actual  weather. 

What  makes  the  air  masses  move,  and  what  makes  them  move 
rhythmically — that  is  the  crowning  one  of  the  great  Norwegian  discov- 
eries. Some  of  it  had  long  been  known.  It  was  understood  that  the  motive 
power  is  the  sun.  By  heating  the  tropics  and  leaving  the  polar  region 
cold,  it  sets  up  a  worldwide  circulation  of  air,  poleward  at  high  altitude, 
equatorward  at  lower  levels.  It  was  understood  that  this  simple  circulation 
is  complicated  by  many  other  factors  such  as  the  monsoon  effect:  conti- 
nents heat  up  in  summer  and  draw  air  in  from  over  the  ocean,  in  winter 
they  cool  and  air  flows  out  over  the  ocean;  there  was  the  baffling  Coriolis 
Force  that  makes  all  moving  things  (on  the  Northern  Hemisphere) 
curve  to  the  right.  In  everyday  life  we  don't  notice  it,  but  some  geogra- 
phers hold  that  it  affects  the  flow  of  rivers,  and  artillerymen  make  allow- 
ance for  it:  a  long-range  gun  is  always  aimed  at  a  spot  hundreds  of  yards 
to  the  left  of  the  target.  The  monsoons  and  the  Coriolis  Force  between 
them  break  up  the  simple  pole-to-equator-to-pole  flow  of  the  air  into  a 
worldwide  complicated  system  of  interlocking  "wheels" — huge  eddies 
that  show  variously  as  tradewinds,  calm  belts,  prevailing  westerlies. 
Charts  have  been  drawn  of  the  air  ocean's  currents  showing  how  air  is 
piled  up  over  some  parts  of  the  world,  rushed  away  from  others. 

But  it  remained  for  the  Norwegians  to  discover  the  polar  front — 
perhaps  the  last-discovered  geographical  thing  on  this  earth.  Bjerknes 
himself  first  saw  it — that  the  worldwide  air  circulation  keeps  piling  up 
new  masses  of  polar  air  in  the  north  and  pressing  them  southward;  it 
keeps  piling  up  new  masses  of  tropical  air  in  the  south,  pressing  them 
northward;  and  thus  forever  keeps  forcing  tropical  and  polar  air  masses 
against  each  other  along  a  front;  that  the  demarcation  line  between 
tropical  air  masses,  pressing  northward,  and  polar  air  masses,  pressing 
southward,  runs  clear  around  the  world:  through  North  America  and 
across  the  Atlantic,  through  Europe  and  across  Siberia,  through  Japan 
and  across  the  Pacific.  The  polar  front  is  clear-cut  in  some  places,  tends 
to  wash  out  in  others;  but  it  always  reestablishes  itself. 

In  summer,  the  polar  front  runs  across  North  America  north  of  the 
Great  Lakes;  in  winter,  it  takes  up  a  position  across  the  United  States. 
Wherever  it  is,  it  keeps  advancing  southward,  retreating  northward, 
much  like  a  battlefront.  And  all  the  cold  fronts  and  warm  fronts  are 
but  sections  of  this  greater  front. 

The  rhythmical  flowing  of  the  air  masses,  the  Norwegians  discovered, 


is  simply  this  wave  action  along  the  polar  front.  Like  all  the  rest  of  the 
modern  weather  concepts,  this  one  becomes  common  sense,  almost  self- 
evident — the  moment  you  realize  that  air  is  stuff,  a  real  fluid  that  has 
density  and  weight.  Except  that  it  occurs  on  a  scale  of  unhuman  mag- 
nitude, wave  action  along  the  polar  front  is  almost  exactly  the  same  thing 
as  waves  on  a  lake. 

In  a  lake,  a  dense,  heavy  fluid — the  water — lies  underneath  a  thin,  light 
fluid — the  air — and  the  result  is  that  rhythmical  welling  up  and  down 
of  the  lake-surface  that  we  call  waves.  Along  the  polar  front,  a  dense, 
heavy  fluid,  the  polar  air,  lies  to  the  north  of  a  thin,  lighter  fluid,  the 
tropical  air;  the  result  is  a  rhythmical  welling  southward  and  northward 
of  the  two  kinds  of  air.  When  a  water  wave  rolls  across  a  lake  its  first 
manifestation  is  a  downward  bulging  of  the  water,  then  an  upward 
surging.  When  a  wave  occurs  in  the  polar  front  it  appears  first  as  a 
northward  surging  of  warm  air,  and  that  means  all  the  phenomena  of  a 
warm  front.  Then,  in  the  rhythmical  backswing,  comes  the  southward 
surging  of  cold  air,  and  that  means  all  the  phenomena  of  a  cold  front. 

These  waves  are  bigger  than  the  imagination  can  easily  encompass. 
They  measure  500  to  1,000  miles  from  crest  to  crest.  When  tropical  air 
surges  northward  it  will  wash  to  the  edge  of  the  Arctic;  when  Polar  air 
surges  southward  it  reaches  down  into  the  tropics.  Such  a  wave  will 
travel  along  the  polar  front  all  the  way  from  somewhere  out  in  the 
Pacific,  across  the  United  States  and  out  to  the  Atlantic;  that  is  the 
meteorological  action  which  underlies  the  recent  novel  Storm  by  George 
Stewart:  the  progress  of  a  wave  along  the  polar  front. 

So  similar  are  these  air  waves  to  the  air-water  waves  of  a  lake  that  there 
are  even  whitecaps  and  breakers.  What  we  call  a  whitecap  or  a  breaker 
is  a  whirling  together  of  air  and  water  into  a  white  foam.  In  the  great 
waves  along  the  polar  front  the  same  toppling-over  can  occur:  warm  and 
cold  air  sometimes  wheel  around  each  other,  underrun  and  overrun  each 
other,  in  a  complicated,  spiral  pattern. 

And  that  is  where  the  old  papery  weather  science  of  the  schoolbooks 
merges  with  the  realistic  observations  of  the  Norwegians.  You  remember 
about  those  Lows  that  were  traveling  across  the  weather  map  and  brought 
with  them  bad  weather.  You  know  how  a  dropping  barometer  has  always 
indicated  the  coming  of  bad  weather — though  we  have  never  quite 
known  why. 

Now  it  turns  out  that  the  barometric  low  is  nothing  but  one  of  those 
toppling-over  waves  in  the  polar  front — or  rather,  it  is  the  way  in  which 
the  spiral  surging  of  the  air  masses  affects  the  barometers.  Look  at  the 
Middle  West  when  it  is  being  swept  by  one  of  those  waves,  take  a  reading 

146  THE  EARTH 

of  everybody's  barometer,  and  you  get  the  typical  low.  Look  at  it  when 
a  low  is  centered,  watch  the  kinds  of  air  that  are  flowing  there,  the  wind 
directions,  the  temperatures  and  humidities  and  you  find  that  a  low  has 
a  definite  internal  structure:  the  typical  wave  pattern,  with  a  warm  air 
mass  going  north  and  a  cold  air  mass  going  south,  both  phases  of  the  same 

Barometric  pressures  turn  out  to  be  not  the  cause  of  the  weather,  but 
simply  a  result,  a  rather  unimportant  secondary  symptom  of  it.  What 
weather  actually  is  the  Norwegians  have  made  clear.  It  is  the  wave 
action  of  the  air  ocean. 




"I  do  not  know  what  1  may  appear  to  the  world,  but  to  myself  I  seem 
to  have  been  only  like  a  boy  playing  on  the  sea-shore,  and  diverting  myself 
in  now  and  then  finding  a  smoother  pebble  and  a  prettier  shell  than  or- 
dinary, whilst  the  great  ocean  of  truth  lay  all  undiscovered  before  me." — 
Sir  Isaac  Newton 

"If  I  have  seen  farther  than  Descartes,  it  is  by  standing  on  the  shoul- 
ders of  giants." — Sir  Isaac  Newton 

"Newton  was  the  greatest  genius  that  ever  existed  and  the  most  for- 
tunate, for  we  cannot  find  more  than  once  a  system  of  the  world  to  estab- 
lish."— Lagrange 

"There  may  have  been  minds  as  happily  constituted  as  his  for  the 
cultivation  of  pure  mathematical  science;  there  may  have  been  minds 
as  happily  constituted  for  the  cultivation  of  science  purely  experimental; 
but  in  no  other  mind  have  the  demonstrative  faculty  and  the  inductive 
faculty  co-existed  in  such  supreme  excellence  and  perfect  harmony." — 
Lord  Macaulay 

"Taking  mathematics  from  the  beginning  of  the  world  to  the  time 
when  Newton  lived,  what  he  had  done  was  much  the  better  half." — 

"Let  Men  Rejoice  that  so  great  a  glory  of  the  human  race  has  ap- 
peared."— Inscription  on  Westminster  Tablet 

"The  law  of  gravitation  is  indisputably  and  incomparably  the  greatest 
scientific  discovery  ever  made,  whether  we  look  at  the  advance  which  it 
involved,  the  extent  of  truth  disclosed,  or  the  fundamental  and  satisfac- 
tory nature  of  this  truth." — William  Whewell 

"Newton's  greatest  direct  contribution  to  optics,  appears  to  be  the 
discovery  and  explanation  of  the  nature  of  color.  He  certainly  laid  the 



broad  foundation  upon  which  spectrum  analysis  rests,  and  out  of  this  has 
come  the  new  science  of  spectroscopy  which  is  the  most  delicate  and 
powerful  method  for  the  investigation  of  the  structure  of  matter. — Dayton 
C.  Miller 

"On  the  day  of  Cromwell's  death,  when  Newton  was  sixteen,  a  great 
storm  raged  all  over  England.  He  used  to  say,  in  his  old  age,  that  on  that 
day  he  made  his  first  purely  scientific  experiment.  To  ascertain  the  force 
of  the  wind,  he  first  jumped  with  the  wind  and  then  against  it,  and  by 
comparing  these  distances  with  the  extent  of  his  own  jump  on  a  calm 
day,  he  was  enabled  to  compute  the  force  of  the  storm.  When  the  wind 
blew  thereafter,  he  used  to  say  it  was  so  many  feet  strong. — fames  Parton 

"His  carriage  was  very  meek,  sedate  and  humble,  never  seemingly 
angry,  of  profound  thought,  his  countenance  mild,  pleasant  and  comely. 
I  cannot  say  I  ever  saw  him  laugh  but  once,  which  put  me  in  mind  of 
the  Ephesian  philosopher,  who  laughed  only  once  in  his  lifetime,  to  see 
an  ass  eating  thistles  when  plenty  of  grass  was  by.  He  always  kept  close 
to  his  studies,  very  rarely  went  visiting  anrJ  had  few  visitors.  I  never 
knew  him  to  take  any  recreation  or  pastime  either  in  riding  out  to  take 
the  air,  walking,  bowling,  or  any  other  exercise  whatever,  thinking  all 
hours  lost  that  were  not  spent  in  his  studies,  to  which  he  kept  so  close 
that  he  seldom  left  his  chamber  except  at  term  time,  when  he  read  in 
the  schools  as  Lucasianus  Professor,  where  so  few  went  to  hear  him,  and 
fewer  that  understood  him,  that  ofttimes  he  did  in  a  manner,  for  want 
of  hearers  read  to  the  walls.  Foreigners  he  received  with  a  great  deal  of 
freedom,  candour,  and  respect.  When  invited  to  a  treat,  which  was  very 
seldom,  he  used  to  return  it  very  handsomely,  and  with  much  satisfac- 
tion to  himself.  So  intent,  so  serious  upon  his  studies,  that  he  ate  very 
sparingly,  nay,  ofttimes  he  has  forgot  to  eat  at  all,  so  that,  going  into  his 
chamber,  I  have  found  his  mess  untouched,  of  which,  when  I  have  re- 
minded him,  he  would  reply — 'Have  I?'  and  then  making  to  the  table 
would  eat  a  bite  or  two  standing,  for  I  cannot  say  I  ever  saw  him  sit  at 
table  by  himself.  He  very  rarely  went  to  bed  till  two  or  three  of  the 
clock,  sometimes  not  until  five  or  six,  lying  about  four  or  five  hours, 
especially  at  spring  and  fall  of  the  leaf,  at  which  times  he  used  to  em- 
ploy about  six  weeks  in  his  elaboratory,  the  fires  scarcely  going  out 
either  night  or  day;  he  sitting  up  one  night  and  I  another  till  he  had  fin- 
ished his  chemical  experiments,  in  the  performance  of  which  he  was  the 
most  accurate,  strict,  exact.  What  his  aim  might  be  I  was  not  able  to 
penetrate  into,  but  his  pains,  his  diligence  at  these  set  times  made  me  think 
he  aimed  at  something  beyond  the  reach  of  human  art  and  industry.  I 


cannot  say  I  ever  saw  him  drink  either  wine,  ale  or  beer,  excepting  at 
meals  and  then  but  very  sparingly.  He  very  rarely  went  to  dine  in  the 
hall,  except  on  some  public  days,  and  then  if  he  has  not  been  minded, 
would  go  very  carelessly,  with  shoes  down  at  heels,  stockings  untied,  sur- 
plice on,  and  his  head  scarcely  combed. 

His  elaboratory  was  well  furnished  with  chemical  materials,  as  bodies, 
receivers,  heads,  crucibles,  etc.  which  was  made  very  litle  use  of,  the 
crucibles  excepted,  in  which  he  fused  his  metals;  he  would  sometimes,  tho' 
very  seldom,  look  into  an  old  mouldy  book  which  lay  in  his  elaboratory, 
I  think  it  was  titled  Agricola  de  Metallis,  the  transmuting  of  metals  being 
his  chief  design,  for  which  purpose  antimony  was  a  great  ingredient.  He 
has  sometimes  taken  a  turn  or  two,  has  made  a  sudden  stand,  turn'd 
himself  about,  run  up  the  stairs  like  another  Archimedes,  with  an  Eureka 
fall  to  write  on  his  desk  standing  without  giving  himself  the  leisure  to 
draw  a  chair  to  sit  down  on.  He  would  with  great  acuteness  answer  a 
question,  but  would  very  seldom  start  one.  Dr.  Boerhave,  in  some  of  his 
writings,  speaking  of  Sir  Isaac:  'That  man/  says  he,  "comprehends  as 
much  as  all  mankind  besides.' — Humphrey  Newton 

"When  we  review  his  life,  his  idiosyncrasies,  his  periods  of  contrast, 
and  his  doubts  and  ambitions  and  desire  for  place,  may  we  not  take  some 
pleasure  in  thinking  of  him  as  a  man — a  man  like  most  other  men  save 
in  one  particular — he  had  genius — a  greater  touch  of  divinity  than  comes 
to  the  rest  of  us? "—David  Eugene  Smith 





of  the  heavens  and  of  our  sea  by  the  power  of  gravity,  but  have 
not  yet  assigned  the  cause  of  this  power.  This  is  certain,  that  it  must 
proceed  from  a  cause  that  penetrates  to  the  very  centres  of  the  sun  and 
planets,  without  suffering  the  least  diminution  of  its  force;  that  operates 
not  according  to  the  quantity  of  the  surfaces  of  the  particles  upon  which 
it  acts  (as  mechanical  causes  used  to  do),  but  according  to  the  quantity 
of  the  solid  matter  which  they  contain,  and  propagates  its  virtue  on  all 
sides  to  immense  distances,  decreasing  always  in  the  duplicate  propor- 
tions of  the  distances.  Gravitation  towards  the  sun  is  made  up  out  of  the 
gravitations  towards  the  several  particles  of  which  the  body  of  the  sun 
is  composed;  and  in  receding  from  the  sun  decreases  accurately  in  the 
duplicate  proportion  of  the  distances  as  far  as  the  orb  of  Saturn,  as  evi- 
dently appears  from  the  quiescence  of  the  aphelions  of  the  planets;  nay, 
and  even  to  the  remotest  aphelions  of  the  comets,  if  these  aphelions  are 
also  quiescent.  But  hitherto  I  have  not  been  able  to  discover  the  cause 
of  those  properties  of  gravity  from  phaenomena,  and  I  frame  no  hypoth- 
eses; for  whatever  is  not  deduced  from  the  phaenomena  is  to  be  called 
an  hypothesis;  and  hypotheses,  whether  metaphysical  or  physical,  whether 
of  occult  qualities  or  mechanical,  have  no  place  in  experimental  phi- 
losophy. In  this  philosophy  particular  propositions  are  inferred  from  the 
phaenomena,  and  afterwards  rendered  general  by  induction.  Thus  it  was 
that  the  impenetrability,  the  mobility,  and  the  impulsive  force  of  bodies, 
and  the  laws  of  motion  and  gravitation  were  discovered.  And  to  us  it  is 
enough  that  gravity  does  really  exist,  and  act  according  to  the  laws  which 
we  have  explained,  and  abundantly  serves  to  account  for  all  the  motions 
of  the  celestial  bodies,  and  of  our  sea. 

From  Newton's  "Principia"  edition  of  1726 



Law  I.  Every  body  perseveres  in  its  state  of  rest,  or  of  uniform  motion 
in  a  right  line,  unless  it  is  compelled  to  change  that  state  by  force  im- 
pressed thereon. 

Projectiles  persevere  in  their  motions,  so  far  as  they  are  not  retarded 
by  the  resistance  of  the  air,  or  impelled  downwards  by  the  force  of  gravity. 
A  top,  whose  parts  by  their  cohesion  are  perpetually  drawn  aside  from 
rectilinear  motions,  does  not  cease  its  rotation,  otherwise  than  as  it  is 
retarded  by  the  air.  The  greater  bodies  of  the  planets  and  comets,  meet- 
ing with  less  resistance  in  more  free  spaces,  preserve  their  motions  both 
progressive  and  circular  for  a  much  longer  time. 

Law  II.  The  alteration  of  motion  is  ever  proportional  to  the  motive 
force  impressed ';  and  is  made  in  the  direction  of  the  right  line  in  which 
that  force  is  impressed. 

If  any  force  generates  a  motion,  a  double  force  will  generate  double 
the  motion,  a  triple  force  triple  the  motion,  whether  that  force  be  im- 
pressed altogether  and  at  once,  or  gradually  and  successively.  And  this 
motion  (being  always  directed  the  same  way  with  the  generating  force), 
if  the  body  moved  before,  is  added  to  or  subducted  from  the  former 
motion,  according  as  they  directly  conspire  with  or  are  directly  contrary 
to  each  other;  or  obliquely  joined,  when  they  are  oblique,  so  as  to  pro- 
duce a  new  motion  compounded  from  the  determination  of  both. 

Law  III.  To  every  action  there  is  always  opposed  an  equal  reaction;  or 
the  mutual  actions  of  two  bodies  upon  each  other  are  always  equal,  and 
directed  to  contrary  parts. 

Whatever  draws  or  presses  another  is  as  much  drawn  or  pressed  by 
that  other.  If  you  press  a  stone  with  your  finger,  the  finger  is  also  pressed 
by  the  stone.  If  a  horse  draws  a  stone  tied  to  a  rope,  the  horse  (if  I  may  so 
say)  will  be  equally  drawn  back  towards  the  stone;  for  the  distended  rope, 
by  the  same  endeavor  to  relax  or  unbend  itself,  will  draw  the  horse 
as  much  towards  the  stone,  as  it  does  the  stone  towards  the  horse,  and 
will  obstruct  the  progress  of  the  one  as  much  as  it  advances  that  of  the 
other.  If  a  body  impinge  upon  another,  and  by  its  force  change  the  mo- 
tion of  the  other,  that  body  also  (because  of  the  equality  of  the  mutual 
pressure)  will  undergo  an  equal  change,  in  its  own  motion,  towards  the 
contrary  part.  The  changes  made  by  these  actions  are  equal,  not  in  the 
velocities  but  in  the  motions  of  bodies;  that  is  to  say,  if  the  bodies  are 
not  hindered  by  any  other  impediments.  For,  because  the  motions  are 
equally  changed,  the  changes  of  the  velocities  made  towards  contrary 
parts  are  reciprocally  proportional  to  the  bodies. 

From  Newton's  "Principia"  edition  of  7726 



In  the  year  1666  (at  which  time  I  applied  myself  to  the  grinding  of 
optick  glasses  of  other  figures  than  spherical)  I  procured  me  a  trian- 
gular glass  prism,  to  try  therewith  the  celebrated  phaenomena  of  colours. 
And  in  order  thereto,  having  darkened  my  chamber,  and  made  a  small 
hole  in  my  window-shuts,  to  let  in  a  convenient  quantity  of  the  sun's 
light,  I  placed  my  prism  at  its  entrance,  that  it  might  be  thereby  re- 
fracted to  the  opposite  wall.  It  was  at  first  a  very  pleasing  divertissement, 
to  view  the  vivid  and  intense  colours  produced  thereby;  but  after  a  while 
applying  myself  to  consider  them  more  circumspectly,  I  became  surprised, 
to  see  them  in  an  oblong  form;  which,  according  to  the  received  laws 
of  refraction,  I  expected  should  have  been  circular.  They  were  terminated 
at  the  sides  with  straight  lines,  but  at  the  ends,  the  decay  of  light  was  so 
gradual  that  it  was  difficult  to  determine  justly,  what  was  their  figure; 
yet  they  seemed  semicircular. 

Comparing  the  length  of  this  coloured  Spectrum  with  its  breadth,  I 
found  it  about  five  times  greater,  a  disproportion  so  extravagant,  that  it 
excited  me  to  a  more  than  ordinary  curiosity  to  examining  from  whence 
it  might  proceed.  I  could  scarce  think,  that  the  various  thicknesses  of 
the  glass,  or  the  termination  with  shadow  or  darkness,  could  have  any 
influence  on  light  to  produce  such  an  effect;  yet  I  thought  it  not  amiss, 
first  to  examine  those  circumstances,  and  so  try'd  what  would  happen 
by  transmitting  light  through  parts  of  the  glass  of  divers  thicknesses,  or 
through  holes  in  the  window  of  divers  bignesses,  or  by  setting  the  prism 
without,  so  that  the  light  might  pass  through  it,  and  be  refracted,  before 
it  was  terminated  by  the  hole:  But  I  found  none  of  these  circumstances 
material.  The  fashion  of  the  colours  was  in  all  these  cases  the  same.  .  .  . 
The  gradual  removal  of  these  suspicions  led  me  to  the  Experimentum 
Crucis,  which  was  this:  I  took  two  boards,  and  placed  one  of  them  close 
behind  the  prism  at  the  window,  so  that  the  light  might  pass  through  a 
small  hole,  made  in  it  for  the  purpose,  and  fall  on  the  other  board,  which 
I  placed  at  about  12  feet  distance,  having  first  made  a  small  hole  in  it 
also,  for  some  of  the  incident  light  to  pass  through.  Then  I  placed  an- 
other prism  behind  this  second  board,  so  that  the  light  trajected  through 
both  the  boards  might  pass  through  that  also,  and  be  again  refracted  be- 
fore it  arrived  at  the  wall.  This  done,  I  took  the  first  prism  in  my  hand, 
and  turned  it  to  and  fro  slowly  about  its  axis,  so  much  as  to  make  the 
several  parts  of  the  image  cast,  on  the  second  board,  successively  pass 
through  the  hole  in  it,  that  I  might  observe  to  what  places  on  the  wall 
the  second  prism  would  refract  them.  And  I  saw  by  the  variation  of  those 


places,  that  the  light,  tending  to  that  end  of  the  image,  towards  which 
the  refraction  of  the  first  prism  was  made,  did  in  the  second  prism  suffer  a 
refraction  considerably  greater  than  the  light  tending  to  the  other  end. 
And  so  the  true  cause  of  the  length  of  that  image  was  detected  to  be  no 
other,  than  that  light  is  not  similar  or  homogenial,  but  consists  of 
Difform  Rays,  some  of  which  are  more  Refrangible  than  others;  so  that 
without  any  difference  in  their  incidence  on  the  same  medium,  some  shall 
be  more  Refracted  than  others;  and  therefore  that,  according  to  their 
particular  Degrees  of  Refrangibility,  they  were  transmitted  through  the 
prism  to  divers  parts  of  the  opposite  wall.  .  .  . 

On  the  Origin  of  Colours 

The  colours  of  all  natural  bodies  have  no  other  origin  than  this,  that 
they  are  variously  qualified,  to  reflect  one  sort  of  light  in  greater  plenty 
than  another.  And  this  I  have  experimented  in  a  dark  room,  by  illumi- 
nating those  bodies  with  uncompounded  light  of  divers  colours.  For  by 
that  means  any  body  may  be  made  to  appear  of  any  colour.  They  have 
there  no  appropriate  colour,  but  ever  appear  of  the  colour  of  the  light 
cast  upon  them,  but  yet  with  this  difference,  that  they  are  most  brisk 
and  vivid  in  the  light  of  their  own  daylight  colour.  Minium  appeareth 
there  of  any  colour  indifferently,  with  which  it  is  illustrated,  but  yet  most 
luminous  in  red,  and  so  bise  appeareth  indifferently  of  any  colour,  but 
yet  most  luminous  in  blue.  And  therefore  minium  reflecteth  rays  of  any 
colour,  but  most  copiously  those  endowed  with  red,  that  is,  with  all 
sorts  of  rays  promiscuously  blended,  those  qualified  with  red  shall  abound 
most  in  that  reflected  light,  and  by  their  prevalence  cause  it  to  appear 
of  that  colour.  And  for  the  same  reason  bise,  reflecting  blue  most  copiously, 
shall  appear  blue  by  the  excess  of  those  rays  in  its  reflected  light;  and 
the  like  of  other  bodies.  And  that  this  is  the  entire  and  adequate  cause 
of  their  colours,  is  manifest,  because  they  have  no  power  to  change  or 
alter  the  colours  of  any  sort  of  rays  incident  apart,  but  put  on  all  colours 
indifferently,  with  which  they  are  enlightened. 

These  things  being  so,  it  can  be  no  longer  disputed,  whether  there  be 
colours  in  the  dark,  or  whether  they  be  the  qualities  of  the  objects  we 
see,  no  nor  perhaps,  whether  light  be  a  body.  For,  since  colours  are  the 
quality  of  light,  having  its  rays  for  their  entire  and  immediate  subject, 
how  can  we  think  those  rays  qualities  also,  unless  one  quality  may  be  the 
subject  of,  and  sustain  another;  which  in  effect  is  to  call  it  substance. 
We  should  not  know  bodies  for  substances;  were  it  not  for  their  sensible 
qualities,  and  the  principle  of  those  being  now  found  due  to  something 
else,  we  have  as  good  reason  to  believe  that  to  be  a  substance  also. 


Besides,  who  ever  thought  any  quality  to  be  a  heterogeneous  aggregate, 
such  as  light  is  discovered  to  be?  But  to  determine  more  absolutely  what 
light  is,  after  what  manner  refracted,  and  by  what  modes  or  actions  it 
produceth  in  our  minds  the  phantasms  of  colours,  is  not  so  easie;  and 
I  shall  not  mingle  conjectures  with  certainties. 

From  Newton's  "A  New  Theory  about  Light  and  Colours,"  1672 

Mathematics,  the  Mirror  of  Civilization 


From  Mathematics  for  the  Million 

npHERE     IS     A     STORY     ABOUT     DIDEROT,     THE 

A  Encyclopaedist  and  materialist,  a  foremost  figure  in  the  intellectual 
awakening  which  immediately  preceded  the  French  Revolution.  Diderot 
was  staying  at  the  Russian  court,  where  his  elegant  flippancy  was  enter- 
taining the  nobility.  Fearing  that  the  faith  of  her  retainers  was  at  stake, 
the  Tsaritsa  commissioned  Euler,  the  most  distinguished  mathematician 
of  the  time,  to  debate  with  Diderot  in  public.  Diderot  was  informed  that  a 
mathematician  had  established  a  proof  of  the  existence  of  God.  He  was 
summoned  to  court  without  being  told  the  name  of  his  opponent.  Before 
the  assembled  court,  Euler  accosted  him  with  the  following  pronounce- 

a  +  bn 

ment,  which  was  uttered  with  due  gravity:  " =  x,  done  Dieu 


existe  repondez!"  Algebra  was  Arabic  to  Diderot.  Unfortunately  he  did 
not  realize  that  was  the  trouble.  Had  he  realized  that  algebra  is  just  a 
language  in  which  we  describe  the  sizes  of  things  in  contrast  to  the 
ordinary  languages  which  we  use  to  describe  the  sorts  of  things  in  the 
world,  he  would  have  asked  Euler  to  translate  the  first  half  of  the  sentence 
into  French.  Translated  freely  into  English,  it  may  be  rendered:  "A 
number  x  can  be  got  by  first  adding  a  number  a  to  a  number  b  multiplied 
bv  itself  a  certain  number  of  timesa  and  then  dividing  the  whole  by  the 


number  of  £'s  multiplied  together.  So  God  exists  after  all.  What  have 
you  got  to  say  now?"  If  Diderot  had  asked  Euler  to  illustrate  the  first 
part  of  his  remark  for  the  clearer  understanding  of  the  Russian  court, 
Euler  might  have  replied  that  x  is  3  when  a  is  i  and  b  is  2  and  n  is  3,  or 
that  x  is  21  when  a  is  3  and  b  is  3  and  n  is  4,  and  so  forth.  Euler's  troubles 
would  have  begun  when  the  court  wanted  to  know  how  the  second  part 
of  the  sentence  follows  from  the  first  part.  Like  many  of  us,  Diderot  had 
stagefright  when  confronted  with  a  sentence  in  size  language.  He  left 
the  court  abruptly  amid  the  titters  of  the  assembly,  confined  himself  to 
his  chambers,  demanded  a  safe  conduct,  and  promptly  returned  to  France. 

Though  he  could  not  know  it,  Diderot  had  the  last  laugh  before  the 
court  of  history.  The  clericalism  which  Diderot  fought  was  overthrown, 
and  though  it  has  never  lacked  the  services  of  an  eminent  mathematician, 
the  supernaturalism  which  Euler  defended  has  been  in  retreat  ever  since. 
One  eminent  contemporary  astronomer  in  his  Gifford  lectures  tells  us  that 
Dirac  has  discovered  p  and  q  numbers.  Done  Dieu  existe.  Another  distin- 
guished astronomer  pauses,  while  he  entertains  us  with  astonishing  calcu- 
lations about  the  distance  of  the  stars,  to  award  M.  le  grand  Architects 
an  honorary  degree  in  mathematics.  There  were  excellent  precedents  long 
before  the  times  of  Euler  and  Diderot.  For  the  first  mathematicians  were 
the  priestly  calendar  makers  who  calculated  the  onset  of  the  seasons.  The 
Egyptian  temples  were  equipped  with  nilometers  with  which  the  priests 
made  painstaking  records  of  the  rising  and  falling  of  the  sacred  river. 
With  these  they  could  predict  the  flooding  of  the  Nile  with  great  accuracy. 
Their  papyri  show  that  they  possessed  a  language  of  measurement  very 
different  from  the  pretentious  phraseology  with  which  they  fobbed  off 
their  prophecies  on  the  laity.  The  masses  could  not  see  the  connection 
between  prophecy  and  reality,  because  the  nilometers  communicated  with 
the  river  by  underground  channels,  skilfully  concealed  from  the  eye  of 
the  people.  The  priests  of  Egypt  used  one  language  when  they  wrote  in 
the  proceedings  of  a  learned  society  and  another  language  when  they  gave 
an  interview  to  the  "sob  sisters"  of  the  Sunday  press. 

In  the  ancient  world  writing  and  reading  were  still  a  mystery  and 
a  craft.  The  plain  man  could  not  decipher  the  Rhind  papyrus  in  which 
the  scribe  Ahmes  wrote  down  the  laws  of  measuring  things.  Civilized 
societies  in  the  twentieth  century  have  democratized  the  reading  and 
writing  of  sort  language.  Consequently  the  plain  man  can  understand 
scientific  discoveries  if  they  do  not  involve  complicated  measurements. 
He  knows  something  about  evolution.  The  priestly  accounts  of  the  crea- 
tion have  fallen  into  discredit.  So  mysticism  has  to  take  refuge  in  the 
atom.  The  atom  is  a  safe  place  not  because  it  is  small,  but  because  you 


have  to  do  complicated  measurements  and  use  underground  channels  to 
find  your  way  there.  These  underground  channels  are  concealed  from 
the  eye  of  the  people  because  the  plain  man  has  not  been  taught  to  read 
and  write  size  language.  Three  centuries  ago,  when  priests  conducted 
their  services  in  Latin,  Protestant  reformers  founded  grammar  schools 
so  that  people  could  read  the  open  bible.  The  time  has  now  come  for 
another  Reformation.  People  must  learn  to  read  and  write  the  language 
of  measurement  so  that  they  can  understand  the  open  bible  of  modern 

In  the  time  of  Diderot  the  lives  and  happiness  of  individuals  might  still 
depend  on  holding  the  correct  beliefs  about  religion.  Today  the  lives  and 
happiness  of  people  depend  more  than  most  of  us  realize  upon  the  correct 
interpretation  of  public  statistics  which  are  kept  by  Government  offices. 
When  a  committee  of  experts  announce  that  the  average  man  can  live 
on  his  unemployment  allowance,  or  the  average  child  is  getting  sufficient 
milk,  the  mere  mention  of  an  average  or  the  citation  of  a  list  of  figures 
is  enough  to  paralyse  intelligent  criticism.  In  reality  half  or  more  than 
half  the  population  may  not  be  getting  enough  to  live  on  when  the 
average  man  or  child  has  enough.  The  majority  of  people  living  today  in 
civilized  countries  cannot  read  and  write  freely  in  size  language,  just  as 
the  majority  of  people  living  in  the  times  of  Wycliff  and  Luther  were 
ignorant  of  Latin  in  which  religious  controversy  was  carried  on.  The 
modern  Diderot  has  got  to  learn  the  language  of  size  in  self-defence, 
because  no  society  is  safe  in  the  hands  of  its  clever  people.  .  .  . 

The  first  men  who  dwelt  in  cities  were  talking  animals.  The  man  of 
the  machine  age  is  a  calculating  animal.  We  live  in  a  welter  of  figures: 
cookery  recipes,  railway  time-tables,  unemployment  aggregates,  fines, 
taxes,  war  debts,  overtime  schedules,  speed  limits,  bowling  averages, 
betting  odds,  billiard  scores,  calories,  babies'  weights,  clinical  temperatures, 
rainfall,  hours  of  sunshine,  motoring  records,  power  indices,  gas-meter 
readings,  bank  rates,  freight  rates,  death  rates,  discount,  interest,  lotteries, 
wave  lengths,  and  tyre  pressures.  Every  night,  when  he  winds  up  his 
watch,  the  modern  man  adjusts  a  scientific  instrument  of  a  precision  and 
delicacy  unimaginable  to  the  most  cunning  artificers  of  Alexandria  in  its 
prime.  So  much  is  commonplace.  What  escapes  our  notice  is  that  in  doing 
these  things  we  have  learnt  to  use  devices  which  presented  tremendous 
difficulties  to  the  most  brilliant  mathematicians  of  antiquity.  Ratios,  limits, 
acceleration,  are  not  remote  abstractions,  dimly  apprehended  by  the 
solitary  genius.  They  are  photographed  upon  every  page  of  our  existence. 
We  have  no  difficulty  in  answering  questions  which  tortured  the  minds 
of  very  clever  mathematicians  in  ancient  times.  This  is  not  because  you 


and  I  are  very  clever  people.  It  is  because  we  inherit  a  social  culture  which 
has  suffered  the  impact  of  material  forces  foreign  to  the  intellectual  life 
of  the  ancient  world.  The  most  brilliant  intellect  is  a  prisoner  within  its 
own  social  inheritance. 

An  illustration  will  help  to  make  this  quite  definite  at  the  outset.  The 
Eleatic  philosopher  Zeno  set  all  his  contemporaries  guessing  by  propound- 
ing a  series  of  conundrums,  of  which  the  one  most  often  quoted  is  the 
paradox  of  Achilles  and  the  tortoise.  Here  is  the  problem  about  which 
the  inventors  of  school  geometry  argued  till  they  had  speaker's  throat  and 
writer's  cramp.  Achilles  runs  a  race  with  the  tortoise.  He  runs  ten  times 
as  fast  as  the  tortoise.  The  tortoise  has  100  yards'  start.  Now,  says  Zeno, 
Achilles  runs  100  yards  and  reaches  the  place  where  the  tortoise  started. 
Meanwhile  the  tortoise  has  gone  a  tenth  as  far  as  Achilles,  and  is  therefore 
10  yards  ahead  of  Achilles.  Achilles  runs  this  10  yards.  Meanwhile  the 
tortoise  has  run  a  tenth  as  far  as  Achilles,  and  is  therefore  i  yard  in  front 
of  him.  Achilles  runs  this  i  yard.  Meanwhile  the  tortoise  has  run  a  tenth 
of  a  yard  and  is  therefore  a  tenth  of  a  yard  in  front  of  Achilles.  Achilles 
runs  this  tenth  of  a  yard.  Meanwhile  the  tortoise  goes  a  tenth  of  a  tenth 
of  a  yard.  He  is  now  a  hundredth  of  a  yard  in  front  of  Achilles.  When 
Achilles  has  caught  up  this  hundredth  of  a  yard,  the  tortoise  is  a  thou- 
sandth of  a  yard  in  front.  So,  argued  Zeno,  Achilles  is  always  getting 
nearer  the  tortoise,  but  can  never  quite  catch  him  up. 

You  must  not  imagine  that  Zeno  and  all  the  wise  men  who  argued  the 
point  failed  to  recognize  that  Achilles  really  did  get  past  the  tortoise. 
What  troubled  them  was,  where  is  the  catch?  You  may  have  been  asking 
the  same  question.  The  important  point  is  that  you  did  not  ask  it  for  the 
same  reason  which  prompted  them.  What  is  worrying  you  is  why  they 
thought  up  funny  little  riddles  of  that  sort.  Indeed,  what  you  are  really 
concerned  with  is  an  historical  problem.  I  am  going  to  show  you  in  a 
minute  that  the  problem  is  not  one  which  presents  any  mathematical 
difficulty  to  you.  You  know  how  to  translate  it  into  size  language,  because 
you  inherit  a  social  culture  which  is  separated  from  theirs  by  the  collapse 
of  two  great  civilizations  and  by  two  great  social  revolutions.  The 
difficulty  of  the  ancients  was  not  an  historical  difficulty.  It  was  a  mathe- 
matical difficulty.  They  had  not  evolved  a  size  language  into  which  this 
problem  could  be  freely  translated. 

The  Greeks  were  not  accustomed  to  speed  limits  and  passenger-luggage 
allowances.  They  found  any  problem  involving  division  very  much  more 
difficult  than  a  problem  involving  multiplication.  They  had  no  way  of 
doing  division  to  any  order  of  accuracy,  because  they  relied  for  calculation 
on  the  mechanical  aid  of  the  counting  frame  or  abacus.  They  could  no^ 


do  sums  on  paper.  For  all  these  and  other  reasons  which  we  shall  meet 
again  and  again,  the  Greek  mathematician  was  unable  to  see  something 
that  we  see  without  taking  the  trouble  to  worry  about  whether  we  see 
it  or  not.  If  we  go  on  piling  up  bigger  and  bigger  quantities,  the  pile  goes 
on  growing  more  rapidly  without  any  end  as  long  as  we  go  on  adding 
more.  If  we  can  go  on  adding  larger  and  larger  quantities  indefinitely 
without  coming  to  a  stop,  it  seemed  to  Zeno's  contemporaries  that  we 
ought  to  be  able  to  go  on  adding  smaller  and  still  smaller  quantities 
indefinitely  without  reaching  a  limit.  They  thought  that  in  one  case  the 
pile  goes  on  for  ever,  growing  more  rapidly,  and  in  the  other  it  goes  on 
for  ever,  growing  more  slowly.  There  was  nothing  in  their  number 
language  to  suggest  that  when  the  engine  slows  beyond  a  certain  point, 
it  chokes  off. 

To  see  this  clearly  we  will  first  put  down  in  numbers  the  distance  which 
the  tortoise  traverses  at  different  stages  of  the  race  after  Achilles  starts. 
As  we  have  described  it  above,  the  tortoise  moves  10  yards  in  stage  i, 
i  yard  in  stage  2,  one-tenth  of  a  yard  in  stage  3,  one-hundredth  of  a  yard 
in  stage  4,  etc.  Suppose  we  had  a  number  language  like  the  Greeks  and 
Romans,  or  the  Hebrews,  who  used  letters  of  the  alphabet.  Using  the  one 
that  is  familiar  to  us  because  it  is  still  used  for  clocks,  graveyards,  and 
law-courts,  we  might  write  the  total  of  all  the  distances  the  tortoise  ran 
before  Achilles  caught  him  up  like  this: 

X  +  I  +   TT  +  -77  +  77  and  so  on. 

We  have  put  "and  so  on"  because  the  ancient  peoples  got  into  great 
difficulties  when  they  had  to  handle  numbers  more  than  a  few  thousands. 
Apart  from  the  fact  that  we  have  left  the  tail  of  the  series  to  your  imagi- 
nation (and  do  not  forget  that  the  tail  is  most  of  the  animal  if  it  goes  on 
for  ever),  notice  another  disadvantage  about  this  script.  There  is  absolutely 
nothing  to  suggest  to  you  how  the  distances  at  each  stage  of  the  race  are 
connected  with  one  another.  Today  we  have  a  number  vocabulary  which 
makes  this  relation  perfectly  evident,  when  we  write  it  down  as: 

i  i  i  i  i  i 

10  +  i  H 1 1 1 1 1 and  so  on. 

10        100        1,000        10,000        100,000        1,000,000 

In  this  case  we  put  "and  so  on"  to  save  ourselves  trouble,  not  because 
we  have  not  the  right  number-words.  These  number-words  were  bor- 
rowed from  the  Hindus,  who  learnt  to  write  number  language  after 
Zeno  and  Euclid  had  gone  to  their  graves.  A  social  revolution,  the 


Protestant  Reformation,  gave  us  schools  which  made  this  number 
language  the  common  property  of  mankind.  A  second  social  upheaval, 
the  French  Revolution,  taught  us  to  use  a  reformed  spelling.  Thanks 
to  the  Education  Acts  of  the  nineteenth  century,  this  reformed  spelling 
is  part  of  the  common  fund  of  knowledge  shared  by  almost  every  sane 
individual  in  the  English-speaking  world.  Let  us  write  the  last  total, 
using  this  reformed  spelling,  which  we  call  decimal  notation.  That  is  to 

10  +  i  +  o-i  +  o-oi  +  o-ooi  +  o-oooi  +  o-ooooi  +  ooooooi  and  so  on. 

We  have  only  to  use  the  reformed  spelling  to  remind  ourselves  that  this 
can  be  put  in  a  more  snappy  form : 

iriiiiii  etc., 
or  still  better: 


We  recognize  the  fraction  o-i  as  a  quantity  that  is  less  than  -ny  and  more 
than  -fa.  If  we  have  not  forgotten  the  arithmetic  we  learned  at  school,  we 
may  even  remember  that  o-i  corresponds  with  the  fraction  %.  This  means 
that,  the  longer  we  make  the  sum,  o-i  +  o-oi  4-  o-ooi,  etc.,  the  nearer  it 
gets  to  £,  and  it  never  grows  bigger  than  £.  The  total  of  all  the  yards 
the  tortoise  moves  till  there  is  no  distance  between  himself  and  Achilles 
makes  up  just  ii£  yards,  and  no  more. 

You  will  now  begin  to  see  what  was  meant  by  saying  that  the  riddle 
presents  no  mathematical  difficulty  to  you.  You  have  a  number  language 
constructed  so  that  it  can  take  into  account  a  possibility  which  mathema- 
ticians describe  by  a  very  impressive  name.  They  call  it  the  convergence 
of  an  infinite  series  to  a  limiting  value.  Put  in  plain  words,  this  only 
means  that,  if  you  go  on  piling  up  smaller  and  smaller  quantities  as  long 
as  you  can,  you  may  get  a  pile  of  which  the  size  is  not  made  measurably 
larger  by  adding  any  more.  The  immense  difficulty  which  the  mathema- 
ticians of  the  ancient  world  experienced  when  they  dealt  with  a  process 
of  division  carried  on  indefinitely,  or  with  what  modern  mathematicians 
call  infinite  series,  limits,  transcendental  numbers,  irrational  quantities, 
and  so  forth,  provides  an  example  of  a  great  social  truth  borne  out  by 
the  whole  history  of  human  knowledge.  Fruitful  intellectual  activity  of 
the  cleverest  people  draws  its  strength  from  the  common  knowledge 
which  all  of  us  share.  Beyond  a  certain  point  clever  people  can  never 
transcend  the  limitations  of  the  social  culture  they  inherit.  When  clever 
people  pride  themselves  on  their  own  isolation,  we  may  well  wonder 
whether  they  are  very  clever  after  all.  Our  studies  in  mathematics  are 


going  to  show  us  that  whenever  the  culture  of  a  people  loses  contact 
with  the  common  life  of  mankind  and  becomes  exclusively  the  plaything 
of  a  leisure  class,  it  is  becoming  a  priestcraft.  It  is  destined  to  end,  as  does 
all  priestcraft,  in  superstition.  To  be  proud  of  intellectual  isolation  from 
the  common  life  of  mankind  and  to  be  disdainful  of  the  great  social  task 
of  education  is  as  stupid  as  it  is  wicked.  It  is  the  end  of  progress  in  knowl- 
edge. History  shows  that  superstitions  are  not  manufactured  by  the  plain 
man.  They  are  invented  by  neurotic  intellectuals  with  too  little  to  do. 
The  mathematician  and  the  plain  man  each  need  one  another.  Maybe  the 
Western  world  is  about  to  be  plunged  irrevocably  into  barbarism.  If  it 
escapes  this  fate,  the  men  and  women  of  the  leisure  state  which  is  now 
within  our  grasp  will  regard  the  democratization  of  mathematics  as  a 
decisive  step  in  the  advance  of  civilization. 

In  such  a  time  as  ours  the  danger  of  retreat  into  barbarism  is  very  real. 
We  may  apply  to  mathematics  the  words  in  which  Cobbett  explained  the 
uses  of  grammar  to  the  working  men  of  his  own  day  when  there  was  no 
public  system  of  free  schools.  In  the  first  of  his  letters  on  English  gram- 
mar for  a  working  boy,  Cobbett  wrote  these  words:  "But,  to  the  acquiring 
of  this  branch  of  knowledge,  my  dear  son,  there  is  one  motive,  which, 
though  it  ought,  at  all  times,  to  be  strongly  felt,  ought,  at  the  present 
time,  to  be  so  felt  in  an  extraordinary  degree.  I  mean  that  desire  which 
every  man,  and  especially  every  young  man,  should  entertain  to  be  able 
to  assert  with  effect  the  rights  and  liberties  of  his  country.  When  you 
come  to  read  the  history  of  those  Laws  of  England  by  which  the  freedom 
of  the  people  has  been  secured  .  .  .  you  will  find  that  tyranny  has  no 
enemy  so  formidable  as  the  pen.  And,  while  you  will  see  with  exultation 
the  long-imprisoned,  the  heavily-fined,  the  banished  William  Prynne, 
returning  to  liberty,  borne  by  the  people  from  Southampton  to  London, 
over  a  road  strewed  with  flowers:  then  accusing,  bringing  to  trial  and  to 
the  block,  the  tyrants  from  whose  hands  he  and  his  country  had  unjustly 
and  cruelly  suffered;  while  your  heart  and  the  heart  of  every  young  man 
in  the  kingdom  will  bound  with  joy  at  the  spectacle,  you  ought  all  to  bear 
in  mind,  that,  without  a  knowledge  of  grammar,  Mr.  Prynne  could 
never  have  performed  any  of  those  acts  by  which  his  name  has  been 
thus  preserved,  and  which  have  caused  his  name  to  be  held  in  honour." 

Today  economic  tyranny  has  no  more  powerful  friend  than  the  cal- 
culating prodigy.  Without  a  knowledge  of  mathematics,  the  grammar 
of  size  and  order,  we  cannot  plan  the  rational  society  in  which  there  will 
be  leisure  for  all  and  poverty  for  none.  If  we  are  inclined  to  be  a  little 
afraid  of  the  prospect,  our  first  step  towards  understanding  this  grammar 
is  to  realize  that  the  reasons  which  repel  many  people  from  studying 


it  are  not  at  all  discreditable.  As  mathematics  has  been  taught  and 
expounded  in  schools  no  effort  is  made  to  show  its  social  history,  its 
significance  in  our  own  social  lives,  the  immense  dependence  of  civilized 
mankind  upon  it.  Neither  as  children  nor  as  adults  are  we  told  how  the 
knowledge  of  this  grammar  has  been  used  again  and  again  throughout 
history  to  assist  in  the  liberation  of  mankind  from  superstition.  We  are 
not  shown  how  it  may  be  used  by  us  to  defend  the  liberties  of  the  people. 
Let  us  see  why  this  is  so. 

The  educational  system  of  North- Western  Europe  was  largely  moulded 
by  three  independent  factors  in  the  period  of  the  Reformation.  One  was 
linguistic  in  the  ordinary  sense.  To  weaken  the  power  of  the  Church  as 
an  economic  overlord  it  was  necessary  to  destroy  the  influence  of  the 
Church  on  the  imagination  of  the  people.  The  Protestant  Reformers 
appealed  to  the  recognized  authority  of  scripture  to  show  that  the  priestly 
practices  were  innovations.  They  had  to  make  the  scriptures  an  open  book. 
The  invention  of  printing  was  the  mechanical  instrument  which  destroyed 
the  intellectual  power  of  the  Pope.  Instruction  in  Latin  and  Greek  was 
a  corollary  of  the  doctrine  of  the  open  bible.  This  prompted  the  great 
educational  innovation  of  John  Knox  and  abetted  the  more  parsimonious 
founding  of  grammar  schools  in  England.  The  ideological  front  against 
popery  and  the  wealthy  monasteries  strengthened  its  strategic  position  by 
new  translations  and  critical  inspection  of  the  scriptural  texts.  That  is  one 
reason  why  classical  scholarship  occupied  a  place  of  high  honour  in  the 
educational  system  of  the  middle  classes. 

The  language  of  size  owes  its  position  in  Western  education  to  two  dif- 
ferent social  influences.  While  revolt  against  the  authority  of  the  Church 
was  gathering  force,  and  before  the  reformed  doctrine  had  begun  to  have 
a  wide  appeal  for  the  merchants  and  craftsmen  of  the  medieval  boroughs, 
the  mercantile  needs  of  the  Hansa  had  already  led  to  the  founding  of 
special  schools  in  Germany  for  the  teaching  of  the  new  arithmetic  which 
Europe  had  borrowed  from  the  Arabs.  An  astonishing  proportion  of  the 
books  printed  in  the  three  years  after  the  first  press  was  set  up  were  com- 
mercial arithmetics.  Luther  vindicated  the  four  merchant  gospels  of 
addition,  subtraction,  multiplication,  and  division  with  astute  political 
sagacity  when  he  announced  the  outlandish  doctrine  that  every  boy  should 
be  taught  to  calculate.  The  grammar  of  numbers  was  chained  down  to 
commercial  uses  before  people  could  foresee  the  vast  variety  of  ways  in 
which  it  was  about  to  invade  man's  social  life. 

Geometry,  already  divorced  from  the  art  of  calculation,  did  not  enter 
into  Western  education  by  the  same  route.  Apart  from  the  stimulus  which 
the  study  of  dead  languages  received  from  the  manufacture  of  bibles, 


classical  pursuits  were  encouraged  because  the  political  theories  of  the 
Greek  philosophers  were  congenial  to  the  merchants  who  were  aspiring  to 
a  limited  urban  democracy.  The  appeal  of  the  city-state  democracy  to  the 
imagination  of  the  wealthier  bourgeois  lasted  till  after  the  French  Revolu- 
tion, when  it  was  laid  to  rest  in  the  familiar  funeral  urns  of  mural  decora- 
tion. The  leisure  class  of  the  Greek  city-states  played  with  geometry  as 
people  play  with  crossword  puzzles  and  chess  today.  Plato  taught  that 
geometry  was  the  highest  exercise  to  which  human  leisure  could  be 
devoted.  So  geometry  became  included  in  European  education  as  a  part  of 
classical  scholarship,  without  any  clear  connection  with  the  contemporary 
reality  of  measuring  Drake's  "world  encompassed."  Those  who  taught 
Euclid  did  not  understand  its  social  use,  and  generations  of  schoolboys 
have  studied  Euclid  without  being  told  how  a  later  geometry,  which 
grew  out  of  Euclid's  teaching  in  the  busy  life  of  Alexandria,  made  it 
possible  to  measure  the  size  of  the  world.  Those  measurements  blew  up 
the  pagan  Pantheon  of  star  gods  and  blazed  the  trail  for  the  great  naviga- 
tions. The  revelation  of  how  much  of  the  surface  of  our  world  was  still 
unexplored  was  the  solid  ground  for  what  we  call  the  faith  of  Columbus. 
Plato's  exaltation  of  mathematics  as  an  august  and  mysterious  ritual  had 
its  roots  in  dark  superstitions  which  troubled,  and  fanciful  puerilities 
which  entranced,  people  who  were  living  through  the  childhood  of 
civilization,  when  even  the  cleverest  people  could  not  clearly  distinguish 
the  difference  between  saying  that  13  is  a  "prime"  number  and  saying 
that  13  is  an  unlucky  number.  His  influence  on  education  has  spread  a  veil 
of  mystery  over  mathematics  and  helped  to  preserve  the  queer  freemasonry 
of  the  Pythagorean  brotherhoods,  whose  members  were  put  to  death  for 
revealing  mathematical  secrets  now  printed  in  school  books.  It  reflects 
no  discredit  on  anybody  if  this  veil  of  mystery  makes  the  subject  distaste- 
ful. Plato's  great  achievement  was  to  invent  a  religion  which  satisfies  the 
emotional  needs  of  people  who  are  out  of  harmony  with  their  social 
environment,  and  just  too  intelligent  or  too  individualistic  to  seek 
sanctuary  in  the  cruder  forms  of  animism.  The  curiosity  of  the  men  who 
first  speculated  about  atoms,  studied  the  properties  of  the  lodestone, 
watched  the  result  of  rubbing  amber,  dissected  animals,  and  catalogued 
plants  in  the  three  centuries  before  Aristotle  wrote  his  epitaph  on  Greek 
science,  had  banished  personalities  from  natural  and  familiar  objects. 
Plato  placed  animism  beyond  the  reach  of  experimental  exposure  by 
inventing  a  world  of  "universals."  This  world  of  universals  was  the  world 
as  God  knows  it,  the  "real"  world  of  which  our  own  is  but  the  shadow. 
In  this  "real"  world  symbols  of  speech  and  number  are  invested  with  the 


magic  which  departed  from  the  bodies  of  beasts  and  the  trunks  of  trees 
as  soon  as  they  were  dissected  and  described.  .  .  . 

Two  views  are  commonly  held  about  mathematics.  One  comes  from 
Plato.  This  is  that  mathematical  statements  represent  eternal  truths.  Plato's 
doctrine  was  used  by  the  German  philosopher,  Kant,  as  a  stick  with  which 
to  beat  the  materialists  of  his  time,  when  revolutionary  writings  like  those 
of  Diderot  were  challenging  priestcraft.  Kant  thought  that  the  principles 
of  geometry  were  eternal,  and  that  they  were  totally  independent  of  our 
sense  organs.  It  happened  that  Kant  wrote  just  before  biologists  dis- 
covered that  we  have  a  sense  organ,  part  of  what  is  called  the  internal  ear, 
sensitive  to  the  pull  of  gravitation.  Since  that  discovery,  the  significance 
of  which  was  first  fully  recognized  by  the  German  physicist,  Ernst  Mach, 
the  geometry  which  Kant  knew  has  been  brought  down  to  earth  by 
Einstein.  It  no  longer  dwells  in  the  sky  where  Plato  put  it.  We  know 
that  geometrical  statements  when  applied  to  the  real  world  are  only 
approximate  truths.  The  theory  of  Relativity  has  been  very  unsettling 
to  mathematicians,  and  it  has  now  become  a  fashion  to  say  that  mathemat- 
ics is  only  a  game.  Of  course,  this  does  not  tell  us  anything  about  mathe- 
matics. It  only  tells  us  something  about  the  cultural  limitations  of  some 
mathematicians.  When  a  man  says  that  mathematics  is  a  game,  he  is 
making  a  private  statement.  He  is  telling  us  something  about  himself,  his 
own  attitude  to  mathematics.  He  is  not  telling  us  anything  about  the 
public  meaning  of  a  mathematical  statement, 

If  mathematics  is  a  game,  there  is  no  reason  why  people  should  play  it 
if  they  do  not  want  to.  With  football,  it  belongs  to  those  amusements 
without  which  life  would  be  endurable.  The  view  which  we  explore  is  that 
mathematics  is  the  language  of  size,  and  that  it  is  an  essential  part  of  the 
equipment  of  an  intelligent  citizen  to  understand  this  language.  If  the 
rules  of  mathematics  are  rules  of  grammar,  there  is  no  stupidity  involved 
when  we  fail  to  see  that  a  mathematical  truth  is  obvious.  The  rules  of 
ordinary  grammar  are  not  obvious.  They  have  to  be  learned.  They  are  not 
eternal  truths.  They  are  conveniences  without  whose  aid  truths  about 
the  sorts  of  things  in  the  world  cannot  be  communicated  from  one  person 
to  another.  In  Cobbett's  memorable  words,  Mr.  Prynne  would  not  have 
been  able  to  impeach  Archbishop  Laud  if  his  command  of  grammar 
had  been  insufficient  to  make  himself  understood.  So  it  is  with  mathe- 
matics, the  grammar  of  size.  The  rules  of  mathematics  are  rules  to  be 
learned.  If  they  are  formidable,  they  are  formidable  because  they  are 
unfamiliar  when  you  first  meet  them — like  gerunds  or  nominative  ab- 
solutes. They  are  also  formidable  because  in  all  languages  there  are  so 
many  rules  and  words  to  memorize  before  we  can  read  newspapers  or 


pick  up  radio  news  from  foreign  stations.  Everybody  knows  that  being 
able  to  chatter  in  several  foreign  languages  is  not  a  sign  of  great  social 
intelligence.  Neither  is  being  able  to  chatter  in  the  language  of  size.  Real 
social  intelligence  lies  in  the  use  of  a  language,  in  applying  the  right 
words  in  the  right  context.  It  is  important  to  know  the  language  of  size, 
because  entrusting  the  laws  of  human  society,  social  statistics,  population, 
man's  hereditary  make-up,  the  balance  of  trade,  to  the  isolated  mathema- 
tician without  checking  his  conclusions  is  like  letting  a  committee  of 
philologists  manufacture  the  truths  of  human,  animal,  or  plant  anatomy 
from  the  resources  of  their  own  imaginations. 

.  .  .  The  language  of  mathematics  differs  from  that  of  everyday  life, 
because  it  is  essentially  a  rationally  planned  language.  The  languages 
of  size  have  no  place  for  private  sentiment,  either  of  the  individual  or 
of  the  nation.  They  are  international  languages  like  the  binomial 
nomenclature  of  natural  history.  In  dealing  with  the  immense  com- 
plexity of  his  social  life  man  has  not  yet  begun  to  apply  inventiveness 
to  the  rational  planning  of  ordinary  language  when  describing  different 
kinds  of  institutions  and  human  behavior.  The  language  of  everyday 
life  is  clogged  with  sentiment,  and  the  science  of  human  nature  has 
not  advanced  so  far  that  we  can  describe  individual  sentiment  in  a 
clear  way.  So  constructive  thought  about  human  society  is  hampered 
by  the  same  conservatism  as  embarrassed  the  earlier  naturalists.  Nowa- 
days people  do  not  differ  about  what  sort  of  animal  is  meant  by  Cimex  or 
Pediculus,  because  these  words  are  only  used  by  people  who  use  them  in 
one  way.  They  still  can  and  often  do  mean  a  lot  of  different  things  when 
they  say  that  a  mattress  is  infested  with  bugs  or  lice.  The  study  of  man's 
social  life  has  not  yet  brought  forth  a  Linnaeus.  So  an  argument  about 
the  "withering  away  of  the  State"  may  disclose  a  difference  about  the 
use  of  the  dictionary  when  no  real  difference  about  the  use  of  the  police- 
man is  involved.  Curiously  enough,  people  who  are  most  sensible  about 
the  need  for  planning  other  social  amenities  in  a  reasonable  way  are  often 
slow  to  see  the  need  for  creating  a  rational  and  international  language. 

The  technique  of  measurement  and  counting  has  followed  the  caravans 
and  galleys  of  the  great  trade  routes.  It  has  developed  very  slowly.  At 
least  four  thousand  years  intervened  between  the  time  when  men  could 
calculate  when  the  next  eclipse  would  occur  and  the  time  when  men  could 
calculate  how  much  iron  is  present  in  the  sun.  Between  the  first  recorded 
observations  of  electricity  produced  by  friction  and  the  measurement  of 
the  attraction  of  an  electrified  body  two  thousand  years  intervened.  Per- 
haps a  longer  period  separates  the  knowledge  of  magnetic  iron  (or  lode- 
stone)  and  the  measurement  of  magnetic  force.  Classifying  things  accord- 


ing  to  size  has  been  a  much  harder  task  than  recognizing  the  different  sorts 
of  things  there  are.  It  has  been  more  closely  related  to  man's  social  achieve- 
ments than  to  his  biological  equipment.  Our  eyes  and  ears  can  recognize 
different  sorts  of  things  at  a  great  distance.  To  measure  things  at  a  dis- 
tance, man  has  had  to  make  new  sense  organs  for  himself,  like  the 
astrolabe,  the  telescope,  and  the  microphone.  He  has  made  scales  which 
reveal  differences  of  weight  to  which  our  hands  are  quite  insensitive.  At 
each  stage  in  the  evolution  of  the  tools  of  measurement  man  has  refined 
the  tools  of  size  language.  As  human  inventiveness  has  turned  from  the 
counting  of  flocks  and  seasons  to  the  building  of  temples,  from  the  build- 
ing of  temples  to  the  steering  of  ships  into  chartless  seas,  from  seafaring 
plunder  to  machines  driven  by  the  forces  of  dead  matter,  new  languages 
of  size  have  sprung  up  in  succession.  Civilizations  have  risen  and  fallen. 
At  each  stage  a  more  primitive,  less  sophisticated  culture  breaks  through 
the  barriers  of  custom  thought,  brings  fresh  rules  to  the  grammar  of 
measurement,  bearing  within  itself  the  limitation  of  further  growth  and  the 
inevitability  that  it  will  be  superseded  in  its  turn.  The  history  of  mathe- 
matics is  the  mirror  of  civilization. 

The  beginnings  of  a  size  language  are  to  be  found  in  the  priestly 
civilizations  of  Egypt  and  Sumeria.  From  these  ancient  civilizations  we 
see  the  first-fruits  of  secular  knowledge  radiated  along  the  inland  trade 
routes  to  China  and  pushing  out  into  and  beyond  the  Mediterranean, 
where  the  Semitic  peoples  are  sending  forth  ships  to  trade  in  tin  and  dyes. 
The  more  primitive  northern  invaders  of  Greece  and  Asia  Minor  collect 
and  absorb  the  secrets  of  the  pyramid  makers  in  cities  where  a  priestly 
caste  is  not  yet  established.  As  the  Greeks  become  prosperous,  geometry 
becomes  a  plaything.  Greek  thought  itself  becomes  corrupted  with  the 
star  worship  of  the  ancient  world.  At  the  very  point  when  it  seems  almost 
inevitable  that  geometry  will  make  way  for  a  new  language,  it  ceases  to 
develop  further.  The  scene  shifts  to  Alexandria,  the  greatest  centre  of  ship- 
ping and  the  mechanical  arts  in  the  ancient  world.  Men  are  thinking  about 
how  much  of  the  world  remains  to  be  explored.  Geometry  is  applied  to  the 
measurement  of  the  heavens.  Trigonometry  takes  its  place.  The  size  of  the 
earth,  the  distance  of  the  sun  and  moon  are  measured.  The  star  gods  are 
degraded.  In  the  intellectual  life  of  Alexandria,  the  factory  of  world 
religions,  the  old  syncretism  has  lost  its  credibility.  It  may  still  welcome 
a  god  beyond  the  sky.  It  is  losing  faith  in  the  gods  within  the  sky. 

In  Alexandria,  where  the  new  language  of  star  measurement  has  its 
beginnings,  men  are  thinking  about  numbers  unimaginably  large 
compared  with  the  numbers  which  the  Greek  intellect  could  grasp. 
Anaxagoras  had  shocked  the  court  of  Pericles  by  declaring  that  the  sun 


was  as  immense  as  the  mainland  of  Greece,  Now  Greece  itself  had  sunk 
into  insignificance  beside  the  world  of  which  Eratosthenes  and  Poseidonius 
had  measured  the  circumference.  The  world  itself  sank  into  insignifi- 
cance beside  the  sun  as  Aristarchus  had  measured  it.  Ere  the  dark  night  of 
monkish  superstition  engulfed  the  great  cosmopolis  of  antiquity,  men  were 
groping  for  new  means  of  calculation.  The  bars  of  the  counting  frame  had 
become  the  bars  of  a  cage  in  which  the  intellectual  life  of  Alexandria  was 
imprisoned.  Men  like  Diophantus  and  Theon  were  using  geometrical 
diagrams  to  devise  crude  recipes  for  calculation.  They  had  almost  invented 
the  third  new  language  of  algebra.  That  they  did  not  succeed  was  the 
nemesis  of  the  social  culture  they  inherited.  In  the  East  the  Hindus  had 
started  from  a  much  lower  level.  Without  the  incubus  of  an  old-established 
vocabulary  of  number,  they  had  fashioned  new  symbols  which  lent  them- 
selves to  simple  calculation  without  mechanical  aids.  The  Moslem  civiliza- 
tion which  swept  across  the  southern  domain  of  the  Roman  Empire 
brought  together  the  technique  of  measurement,  as  it  had  evolved  in  the 
hands  of  the  Greeks  and  the  Alexandrians,  adding  the  new  instrument 
for  handling  numbers  which  was  developed  through  the  invention  of  the 
Hindu  number  symbols.  In  the  hands  of  Arabic  mathematicians  like  Omar 
Khayyam,  the  main  features  of  a  language  of  calculation  took  shape.  We 
still  call  it  by  the  Arabic  name,  algebra.  We  owe  algebra  and  the  pattern 
of  modern  European  poetry  to  a  non-Aryan  people  who  would  be  excluded 
from  the  vote  in  the  Union  of  South  Africa. 

Along  the  trade  routes  this  new  arithmetic  is  brought  into  Europe 
by  Jewish  scholars  from  the  Moorish  universities  of  Spain  and  by  Gentile 
merchants  trading  with  the  Levant,  some  of  them  patronized  by  nobles 
whose  outlook  had  been  unintentionally  broadened  by  the  Crusades. 
Europe  stands  on  the  threshold  of  the  great  navigations.  Seafarers  are 
carrying  Jewish  astronomers  who  can  use  the  star  almanacs  which  Arab 
scholarship  had  prepared.  The  merchants  are  becoming  rich.  More  than 
ever  the  world  is  thinking  in  large  numbers.  The  new  arithmetic  or 
"algorithm"  sponsors  an  amazing  device  which  was  prompted  by  the  need 
for  more  accurate  tables  of  star  measurement  for  use  in  seafaring.  Loga- 
rithms were  among  the  cultural  first-fruits  of  the  great  navigations.  Mathe- 
maticians are  thinking  in  maps,  in  latitude  and  longitude.  A  new  kind 
of  geometry  (what  we  call  graphs  in  everyday  speech)  was  an  inevitable 
consequence.  This  new  geometry  of  Descartes  contains  something  which 
Greek  geometry  had  left  out.  In  the  leisurely  world  of  antiquity  there  were 
no  clocks.  In  the  bustling  world  of  the  great  navigations  mechanical 
clocks  are  displacing  the  ancient  ceremonial  function  of  the  priesthood  as 
timekeepers.  A  geometry  which  could  represent  time  and  a  religion  in 


which  there  were  no  saints'  days  are  emerging  from  the  same  social 
context.  From  this  geometry  of  time  a  group  of  men  who  were  studying 
the  mechanics  of  the  pendulum  clock  and  making  fresh  discoveries  about 
the  motion  of  the  planets  devised  a  new  size  language  to  measure  motion. 
Today  we  call  it  "the"  calculus. 

This  crude  outline  of  the  history  of  mathematics  as  a  mirror  of  civiliza- 
tion, interlocking  with  man's  common  culture,  his  inventions,  his  economic 
arrangements,  his  religious  beliefs,  may  be  left  at  the  stage  which  had  been 
reached  when  Newton  died.  What  has  happened  since  has  been  largely 
the  filling  of  gaps,  the  sharpening  of  instruments  already  devised.  Here 
and  there  are  indications  of  a  new  sort  of  mathematics.  We  see  a  hint  of 
it  in  social  statistics  and  the  study  of  the  atom.  We  begin  to  see  possi- 
bilities of  new  languages  of  size  transcending  those  we  now  use,  as  the 
calculus  of  movement  gathered  into  itself  all  that  had  gone  before. 


Experiments  and  Ideas 



As  frequent  mention  is  made  in  public  papers  from  Europe  of  the 
success  of  the  Philadelphia  experiment  for  drawing  the  electric  fire  from 
clouds  by  means  of  pointed  rods  of  iron  erected  on  high  buildings,  &,  it 
may  be  agreeable  to  the  curious  to  be  informed,  that  the  same  experi- 
ment has  succeeded  in  Philadelphia,  though  made  in  a  different  and 
more  easy  manner,  which  is  as  follows: 

Make  a  small  cross  of  two  light  strips  of  cedar,  the  arms  so  long  as  to 
reach  to  the  four  corners  of  a  large  thin  silk  handkerchief  when  extended; 
tie  the  corners  of  the  handkerchief  to  the  extremities  of  the  cross,  so  you 
have  the  body  of  a  kite;  which  being  properly  accommodated  with  a 
tail,  loop,  and  string,  will  rise  in  the  air,  like  those  made  of  paper;  but 
this  being  of  silk,  is  fitter  to  bear  the  wet  and  wind  of  a  thunder-gust 
without  tearing.  To  the  top  of  the  upright  stick  of  the  cross  is  to  be  fixed 
a  very  sharp  pointed  wire,  rising  a  foot  or  more  above  the  wood.  To 
the  end  of  the  twine,  next  the  hand,  is  to  be  tied  a  silk  ribbon,  and  where 
the  silk  and  twine  join,  a  key  may  be  fastened.  This  kite  is  to  be  raised 
when  a  thunder-gust  appears  to  be  coming  on,  and  the  person  who  holds 
the  string  must  stand  within  a  door  or  window  or  under  some  cover, 
so  that  the  silk  ribbon  may  not  be  wet;  and  care  must  be  taken  that  the 
twine  does  not  touch  the  frame  of  the  door  or  window.  As  soon  as  any  of 
the  thunder-clouds  come  over  the  kite,  the  pointed  wire  will  draw  the 
electric  fire  from  them,  and  the  kite,  with  all  the  twine,  will  be  electrified, 
and  the  loose  filaments  of  the  twine  will  stand  out  every  way,  and  be 
attracted  by  an  approaching  finger.  And  when  the  rain  has  wet  the  kite 
and  twine,  so  that  it  can  conduct  the  electric  fire  freely,  you  will  find  it 
stream  out  plentifully  from  the  key  on  the  approach  of  your  knuckle. 
At  this  key  the  phial  may  charged;  and  from  electric  fire  thus  obtained, 
spirits  may  be  kindled,  and  all  the  other  electric  experiments  be  per- 



formed,  which  are  usually  done  by  the  help  of  a  rubbed  glass  globe  or 
tube,  and  thereby  the  sameness  of  the  electric  matter  with  that  of  lightning 
completely  demonstrated.  Letter  to  Peter  Collinson,  1752 


Your  question,  how  I  came  first  to  think  of  proposing  the  experiment 
of  drawing  down  the  lightning,  in  order  to  ascertain  its  sameness  with 
the  electric  fluid,  I  cannot  answer  better  than  by  giving  you  an  extract 
from  the  minutes  I  used  to  keep  of  the  experiments  I  made,  with 
memorandums  of  such  as  I  purposed  to  make,  the  reasons  for  making 
them,  and  the  observations  that  arose  upon  them,  from  which  minutes  my 
letters  were  afterwards  drawn.  By  this  extract  you  will  see,  that  the 
thought  was  not  so  much  "an  out-of-the-way  one,"  but  that  it  might 
have  occurred  to  any  electrician. 

"November  7,  1749.  Electrical  fluid  agrees  with  lightning  in  these  par- 
ticulars, i.  Giving  light.  2.  Colour  of  the  light.  3.  Crooked  direction. 
4.  Swift  motion.  5.  Being  conducted  by  metals.  6.  Crack  or  noise  in  explod- 
ing. 7.  Subsisting  in  water  or  ice.  8.  Rending  bodies  it  passes  through. 
9.  Destroying  animals.  10.  Melting  metals,  n.  Firing  inflammable  sub- 
stances. 12.  Sulphureous  smell.  The  electric  fluid  is  attracted  by  points. 
We  do  not  know  whether  this  property  is  in  lightning.  But  since  they 
agree  in  all  particulars  wherein  we  can  already  compare  them,  is  it  not 
probable  they  agree  likewise  in  this  ?  Let  the  experiment  be  made." .  .  „ 

The  knocking  down  of  the  six  men  was  performed  with  two  of  my 
large  jarrs  not  fully  charged.  I  laid  one  end  of  my  discharging  rod  upon 
the  head  of  the  first;  he  laid  his  hand  on  the  head  of  the  second;  the 
second  his  hand  on  the  head  of  the  third,  and  so  to  the  last,  who  held, 
in  his  hand,  the  chain  that  was  connected  with  the  outside  of  the  jarrs. 
When  they  were  thus  placed,  I  applied  the  other  end  of  my  rod  to  the 
prime-conductor,  and  they  all  dropt  together.  When  they  got  up,  they  all 
declared  they  had  not  felt  any  stroke,  and  wondered  how  they  came  to 
fall;  nor  did  any  of  them  either  hear  the  crack,  or  see  the  light  of  it. 
You  suppose  it  a  dangerous  experiment;  but  I  had  once  suffered  the  same 
myself,  receiving,  by  accident,  an  equal  stroke  through  my  head,  that 
struck  me  down,  without  hurting  me:  And  I  had  seen  a  young  woman, 
that  was  about  to  be  electrified  through  the  feet,  (for  some  indisposition) 
receive  a  greater  charge  through  the  head,  by  inadvertently  stooping  for- 
ward to  look  at  the  placing  of  her  feet,  till  her  forhead  (as  she  was  very 
tall)  came  too  near  my  prime-conductor:  she  dropt,  but  instantly  got  up 


again,  complaining  o£  nothing.  A  person  so  struck,  sinks  down  doubled, 
or  folded  together  as  it  were,  the  joints  losing  their  strength  and  stiffness 
at  once,  so  that  he  drops  on  the  spot  where  he  stood,  instantly,  and  there 
is  no  previous  staggering,  nor  does  he  ever  fall  lengthwise.  Too  great  a 
charge  might,  indeed,  kill  a  man,  but  I  have  not  yet  seen  any  hurt  done 
by  it.  It  would  certainly,  as  you  observe,  be  the  easiest  of  all  deaths.  .  .  - 

Letter  to  John  Lining,  7755 


Agreeable  to  your  request,  I  send  you  my  reasons  for  thinking  that  our 
northeast  storms  in  North  America  begin  first,  in  point  of  time,  in  the 
southwest  parts:  That  is  to  say,  the  air  in  Georgia,  the  farthest  of  our 
colonies  to  the  Southwest,  begins  to  move  southwesterly  before  the  air 
of  Carolina,  which  is  the  next  colony  northeastward;  the  air  of  Carolina 
has  the  same  motion  before  the  air  of  Virginia,  which  lies  still  more 
northeastward;  and  so  on  northeasterly  through  Pennsylvania,  New-York, 
New-England,  &c.,  quite  to  Newfoundland. 

These  northeast  storms  are  generally  very  violent,  continue  sometimes 
two  or  three  days,  and  often  do  considerable  damage  in  the  harbours 
along  the  coast.  They  are  attended  with  thick  clouds  and  rain. 

What  first  gave  me  this  idea,  was  the  following  circumstance.  About 
twenty  years  ago,  a  few  more  or  less,  I  cannot  from  my  memory  be  cer- 
tain, we  were  to  have  an  eclipse  of  the  moon  at  Philadelphia,  on  a  Fri- 
day evening,  about  nine  o'clock.  I  intended  to  observe  it,  but  was  pre- 
vented by  a  northeast  storm,  which  came  on  about  seven,  with  thick 
clouds  as  usual,  that  quite  obscured  the  whole  hemisphere.  Yet  when  the 
post  brought  us  the  Boston  newspaper,  giving  an  account  of  the  effects 
of  the  same  storm  in  those  parts,  I  found  the  beginning  of  the  eclipse 
had  been  well  observed  there,  though  Boston  lies  N.  E.  of  Philadelphia 
about  400  miles.  This  puzzled  me  because  the  storm  began  with  us  so 
soon  as  to  prevent  any  observation,  and  being  a  N.  E.  storm,  I  imagined 
it  must  have  begun  rather  sooner  in  places  farther  to  the  northeastward 
than  it  did  at  Philadelphia.  I  therefore  mentioned  it  in  a  letter  to  my 
brother,  who  lived  at  Boston;  and  he  informed  me  the  storm  did  not 
begin  with  them  till  near  eleven  o'clock,  so  that  they  had  a  good  observa- 
tion of  the  eclipse:  And  upon  comparing  all  the  other  accounts  I  received 
from  the  several  colonies,  of  the  time  of  beginning  of  the  same  storm,  and, 
since  that  of  other  storms  of  the  same  kind,  1^  found  the  beginning  to 
be  always  later  the  farther  northeastward.  I  have  not  my  notes  with  me 


here  in  England,  and  cannot,  from  memory,  say  the  proportion  o£  time 
to  distance,  but  I  think  it  is  about  an  hour  to  every  hundred  miles. 

From  thence  I  formed  an  idea  of  the  cause  of  these  storms,  which  I 
would  explain  by  a  familiar  instance  or  two.  Suppose  a  long  canal  of 
water  stopp'd  at  the  end  by  a  gate.  The  water  is  quite  at  rest  till  the 
gate  is  open,  then  it  begins  to  move  out  through  the  gate;  the  water  next 
the  gate  is  first  in  motion,  and  moves  towards  the  gate;  the  water  next 
to  that  first  water  moves  next,  and  so  on  successively,  till  the  water  at 
the  head  of  the  canal  is  in  motion,  which  is  last  of  all.  In  this  case  all  the 
water  moves  indeed  towards  the  gate,  but  the  successive  times  of  begin- 
ning motion  are  the  contrary  way,  viz.  from  the  gate  backwards  to  the 
head  of  the  canal.  Again,  suppose  the  air  in  a  chamber  at  rest,  no  cur- 
rent through  the  room  till  you  make  a  fire  in  the  chimney.  Immediately 
the  air  in  the  chimney,  being  rarefied  by  the  fire,  rises;  the  air  next  the 
chimney  flows  in  to  supply  its  place,  moving  towards  the  chimney;  and, 
in  consequence,  the  rest  of  the  air  successively,  quite  back  to  the  door. 
Thus  to  produce  our  northeast  storms,  I  suppose  some  great  heat  and 
rarefaction  of  the  air  in  or  about  the  Gulph  of  Mexico;  the  air  thence 
rising  has  its  place  supplied  by  the  next  more  northern,  cooler,  and  there- 
fore denser  and  heavier,  air;  that,  being  in  motion,  is  followed  by  the 
next  more  northern  air,  &c.  &c.,  in  a  successive  current,  to  which  current 
our  coast  and  inland  ridge  of  mountains  give  the  direction  of  northeast, 
as  they  lie  N.E.  and  S.W.  Letter  to  Alexander  Small,  1760 


I  have  this  day  received  your  favor  of  the  2d  inst.  Every  information 
in  my  power,  respecting  the  balloons,  I  sent  you  just  before  Christmas, 
contained  in  copies  of  my  letters  to  Sir  Joseph  Banks.  There  is  no  secret 
in  the  affair,  and  I  make  no  doubt  that  a  person  coming  from  you  would 
easily  obtain  a  sight  of  the  different  balloons  of  Montgolfier  and  Charles, 
with  all  the  instructions  wanted;  and,  if  you  undertake  to  make  one, 
I  think  it  extremely  proper  and  necessary  to  send  an  ingenious  man  here 
for  that  purpose;  otherwise,  for  want  of  attention  to  some  particular  cir- 
cumstance, or  of  not  being  acquainted  with  it,  the  experiment  might  mis- 
carry, which,  in  an  affair  of  so  much  public  expectation,  would  have 
bad  consequences,  draw  upon  you  a  great  deal  of  censure,  and  affect  your 
reputation.  It  is  a  serious  thing  to  draw  out  from  their  affairs  all  the 
inhabitants  of  a  great  city  and  its  environs,  and  a  disappointment  makes 
them  angry.  At  Bourdeaux  lately  a  person  who  pretended  to  send  up  a 
balloon,  and  had  received  money  from  many  people,  not  being  able  to 


make  it  rise,  the  populace  were  so  exasperated  that  they  pulled  down  his 
house  and  had  like  to  have  killed  him. 

It  appears,  as  you  observe,  to  be  a  discovery  of  great  importance,  and 
what  may  possibly  give  a  new  turn  to  human  affairs.  Convincing 
sovereigns  of  the  folly  of  wars  may  perhaps  be  one  effect  of  it;  since  it  will 
be  impracticable  for  the  most  potent  of  them  to  guard  his  dominions. 
Five  thousand  balloons,  capable  of  raising  two  men  each,  could  not  cost 
more  than  five  ships  of  the  line;  and  where  is  the  prince  who  can  afford 
so  to  cover  his  country  with  troops  for  its  defence,  as  that  ten  thousand 
men  descending  from  the  clouds  might  not  in  many  places  do  an  infi- 
nite deal  of  mischief,  before  a  force  could  be  brought  together  to  repel 
them?  ,  .  .  Letter  to  Jan  Ingcnhousz,  1784 


You  often  entertain  us  with  accounts  of  new  discoveries.  Permit  me  to 
communicate  to  the  public,  through  your  paper,  one  that  has  lately  been 
made  by  myself,  and  which  I  conceive  may  be  of  great  utility. 

I  was  the  other  evening  in  a  grand  company,  where  the  new  lamp  of 
Messrs.  Quinquet  and  Lange  was  introduced,  and  much  admired  for  its 
splendour;  but  a  general  inquiry  was  made,  whether  the  oil  it  consumed 
was  not  in  proportion  to  the  light  it  afforded,  in  which  case  there  would 
be  no  saving  in  the  use  of  it.  No  one  present  could  satisfy  us  in  that 
point,  which  all  agreed  ought  to  be  known,  it  being  a  very  desirable 
thing  to  lessen,  if  possible,  the  expense  of  lighting  our  apartments,  when 
every  other  article  of  family  expense  was  so  much  augmented. 

I  was  pleased  to  see  this  general  concern  for  economy,  for  I  love  economy 

I  went  home,  and  to  bed,  three  or  four  hours  after  midnight,  with  my 
head  full  of  the  subject.  An  accidental  sudden  noise  waked  me  about  six 
in  the  morning,  when  I  was  surprised  to  find  my  room  filled  with  light; 
and  I  imagined  at  first,  that  a  number  of  those  lamps  had  been  brought 
into  it;  but,  rubbing  my  eyes,  I  perceived  the  light  came  in  at  the  win- 
dows. I  got  up  and  looked  out  to  see  what  might  be  the  occasion  of  it, 
when  I  saw  the  sun  just  rising  above  the  horizon,  from  where  he  poured 
his  rays  plentifully  into  my  chamber,  my  domestic  having  negligently 
omitted,  the  preceding  evening,  to  close  the  shutters. 

I  looked  at  my  watch,  which  goes  very  well,  and  found  that  it  was  but 
six  o'clock;  and  still  thinking  it  something  extraordinary  that  the  sun 
should  rise  so  early,  I  looked  into  the  almanac,  where  I  found  it  to  be  the 
hour  given  for  his  rising  on  that  day.  I  looked  forward,  too,  and  found  he 


was  to  rise  still  earlier  every  day  till  towards  the  end  of  June;  and  that 
at  no  time  in  the  year  he  retarded  his  rising  so  long  as  till  eight  o'clock. 
Your  readers,  who  with  me  have  never  seen  any  signs  of  sunshine  before 
noon,  and  seldom  regard  the  astronomical  part  of  the  almanac,  will  be  as 
much  astonished  as  I  was,  when  they  hear  of  his  rising  so  early;  and 
especially  when  I  assure  them,  that  he  gives  light  as  soon  as  he  rises.  I 
am  convinced  of  this.  I  am  certain  of  my  fact.  One  cannot  be  more 
certain  of  any  fact.  I  saw  it  with  my  own  eyes.  And,  having  repeated 
this  observation  the  three  following  mornings,  I  found  always  precisely 
the  same  result. .  .  . 

This  event  has  given  rise  in  my  mind  to  several  serious  and  important 
reflections.  I  considered  that,  if  I  had  not  been  awakened  so  early  in  the 
morning,  I  should  have  slept  six  hours  longer  by  the  light  of  the  sun, 
and  in  exchange  have  lived  six  hours  the  following  night  by  candle- 
light; and,  the  latter  being  a  much  more  expensive  light  than  the  former, 
my  love  of  economy  induced  me  to  muster  up  what  little  arithmetic  I  was 
master  of,  and  to  make  some  calculations,  which  I  shall  give  you,  after 
observing  that  utility  is,  in  my  opinion  the  test  of  value  in  matters  of 
invention,  and  that  a  discovery  which  can  be  applied  to  no  use,  or  is  not 
good  for  something,  is  good  for  nothing. 

I  took  for  the  basis  of  my  calculation  the  supposition  that  there  are  one 
hundred  thousand  families  in  Paris,  and  that  these  families  consume  in 
the  night  half  a  pound  of  bougies,  or  candles,  per  hour.  I  think  this  is  a 
moderate  allowance,  taking  one  family  with  another;  for  though,  I  believe 
some  consume  less,  I  know  that  many  consume  a  great  deal  more.  Then 
estimating  seven  hours  per  day  as  the  medium  quantity  between  the 
time  of  the  sun's  rising  and  ours,  he  rising  during  the  six  following 
months  from  six  to  eight  hours  before  noon,  and  there  being  seven  hours 
of  course  per  night  in  which  we  burn  candles,  the  account  will  stand 
thus; — 

In  the  six  months  between  the  20th  of  March  and  the  2oth  of  September, 
there  are 

Nights  183 

Hours  of  each  night  in  which  we  burn  candles  7 

Multiplication  gives  for  the  total  number  of  hours  1,281 

These  1,281  hours  multiplied  by  100,000,  the  number  of 

inhabitants,  give  128,100,000 

One  hundred  twenty-eight  millions  and  one  hundred  thousand 
hours,  spent  at  Paris  by  candle-light,  which,  at  half  a  pound 
of  wax  and  tallow  per  hour,  gives  the  weight  of  64,050,000 


Sixty-four  millions  and  fifty  thousand  of  pounds,  which,  esti- 
mating the  whole  at  the  medium  price  of  thirty  sols  the 
pound,  makes  the  sum  of  ninety-six  millions  and  seventy- 
five  thousand  livres  tournois  96,075,000 

An  immense  sum!  that  the  city  of  Paris  might  save  every  year,  by  the 
economy  of  using  sunshine  instead  of  candles.  . . . 

Letter  to  the  Authors  of  "The  Journal  of  Paris,"  1784 


By  Mr.  Dollond's  saying,  that  my  double  spectacles  can  only  serve  par- 
ticular eyes,  I  doubt  he  has  not  been  rightly  informed  of  their  construc- 
tion. I  imagine  it  will  be  found  pretty  generally  true,  that  the  same 
convexity  of  glass,  through  which  a  man  sees  clearest  and  best  at  the 
distance  proper  for  reading,  is  not  the  best  for  greater  distances.  I  there- 
fore had  formerly  two  pair  of  spectacles,  which  I  shifted  occasionally,  as 
in  travelling  I  sometimes  read,  and  often  wanted  to  regard  the  prospects. 
Finding  this  change  troublesome,  and  not  always  sufficiently  ready,  I  had 
the  glasses  cut,  and  half  of  each  kind  associated  in  the  same  circle.  .  .  . 

By  this  means,  as  I  wear  my  spectacles  constantly,  I  have  only  to  move 
my  eyes  up  or  down,  as  I  want  to  see  distinctly  far  or  near,  the  proper 
glasses  being  always  ready.  This  I  find  more  particularly  convenient  since 
my  being  in  France,  the  glasses  that  serve  me  best  at  table  to  see  what 
I  eat,  not  being  the  best  to  see  the  faces  of  those  on  the  other  side  of  the 
table  who  speak  to  me;  and  when  one's  ears  are  not  well  accustomed  to 
the  sounds  of  a  language,  a  sight  of  the  movements  in  the  features  of  him 
that  speaks  helps  to  explain;  so  that  I  understand  French  better  by  the 
help  of  my  spectacles.  Letter  to  George  Whatley,  1785 

Exploring  the  Atom 


From  The  Universe  Around  Us 

-£*»  Greek  philosophy  was  greatly  exercised  by  the  question  of  whether 
in  the  last  resort  the  ultimate  substance  of  the  universe  was  continuous  or 
discontinuous.  We  stand  on  the  sea-shore,  and  all  around  us  see  stretches 
of  sand  which  appear  at  first  to  be  continuous  in  structure,  but  which  a 
closer  examination  shews  to  consist  of  separate  hard  particles  or  grains. 
In  front  rolls  the  ocean,  which  also  appears  at  first  to  be  continuous  in 
structure,  and  this  we  find  we  cannot  divide  into  grains  or  particles,  no 
matter  how  we  try.  We  can  divide  it  into  drops,  but  then  each  drop  can 
be  subdivided  into  smaller  drops,  and  there  seems  to  be  no  reason,  on  the 
face  of  things,  why  this  process  of  subdivision  should  not  be  continued 
for  ever.  The  question  which  agitated  the  Greek  philosophers  was,  in 
effect,  whether  the  water  of  the  ocean  or  the  sand  of  the  sea-shore  gave 
the  truest  picture  of  the  ultimate  structure  of  the  substance  of  the  universe. 

The  "atomic"  school,  founded  by  Dernocritus,  Leucippus  and  Lucretius, 
believed  in  the  ultimate  discontinuity  of  matter;  they  taught  that  any 
substance,  after  it  had  been  subdivided  a  sufficient  number  of  times,  would 
be  found  to  consist  of  hard  discrete  particles  which  did  not  admit  of 
further  subdivision.  For  them  the  sand  gave  a  better  picture  of  ultimate 
structure  than  the  water,  because  they  thought  that  sufficient  subdivision 
would  cause  the  water  to  display  the  granular  properties  of  sand.  And  this 
intuitional  conjecture  is  amply  confirmed  by  modern  science. 

The  question  is,  in  effect,  settled  as  soon  as  a  thin  layer  of  a  substance 
is  found  to  shew  qualities  essentially  different  from  those  of  a  slightly 
thicker  layer.  A  layer  of  yellow  sand  swept  uniformly  over  a  red  floor 
will  make  the  whole  floor  appear  yellow  if  there  is  enough  sand  to  make 
a  layer  at  least  one  grain  thick.  If,  however,  there  is  only  half  this  much 
sand,  the  redness  of  the  floor  inevitably  shews  through;  it  is  impossible 
to  spread  sand  in  a  uniform  layer  only  half  a  grain  thick.  This  abrupt 



change  in  the  properties  of  a  layer  o£  sand  is  of  course  a  consequence  of 
the  granular  structure  of  sand. 

Similar  changes  are  found  to  occur  in  the  properties  of  thin  layers  of 
liquid.  A  teaspoonful  of  soup  will  cover  the  bottom  of  a  soup  plate,  but  a 
single  drop  of  soup  will  only  make  an  untidy  splash.  In  some  cases  it  is 
possible  to  measure  the  exact  thickness  of  layer  at  which  the  properties 
of  liquids  begin  to  change.  In  1890  Lord  Rayleigh  found  that  thin  films 
of  olive  oil  floating  on  water  changed  their  properties  entirely  as  soon  as 
the  thickness  of  the  film  was  reduced  to  below  a  millionth  of  a  millimetre 
(or  a  25,ooo,oooth  part  of  an  inch).  The  obvious  interpretation,  which  is 
confirmed  in  innumerable  ways,  is  that  olive  oil  consists  of  discrete 
particles — analogous  to  the  "grains"  in  a  pile  of  sand — each  having  a 
diameter  somewhere  in  the  neighbourhood  of  a  25,ooo,oooth  part  of  an 

Every  substance  consists  of  such  "grains";  they  are  called  molecules. 
The  familiar  properties  of  matter  are  those  of  layers  many  molecules 
thick;  the  properties  of  layers  less  than  a  single  molecule  thick  are  known 
only  to  the  physicist  in  his  laboratory. 


How  are  we  to  break  up  a  piece  of  substance  into  its  ultimate  grains, 
or  molecules?  It  is  easy  for  the  scientist  to  say  that,  by  subdividing  water 
for  long  enough,  we  shall  come  to  grains  which  cannot  be  subdivided  any 
further;  the  plain  man  would  like  to  see  it  done. 

Fortunately  the  process  is  one  of  extreme  simplicity.  Take  a  glass  of 
water,  apply  gentle  heat  underneath,  and  the  water  begins  to  evaporate. 
What  does  this  mean?  It  means  that  the  water  is  being  broken  up  into 
its  separate  ultimate  grains  or  molecules.  If  the  glass  of  water  could  be 
placed  on  a  sufficiently  sensitive  spring  balance,  we  should  see  that  the 
process  of  evaporation  does  not  proceed  continuously,  layer  after  layer, 
but  jerkily,  moleciile  by  molecule.  We  should  find  the  weight  of  the 
water  changing  by  jumps,  each  jump  representing  the  weight  of  a  single 
molecule.  The  glass  may  contain  any  integral  number  of  molecules  but 
never  fractional  numbers — if  fractions  of  a  molecule  exist,  at  any  rate 
they  do  not  come  into  play  in  the  evaporation  of  a  glass  of  water. 

THE  GASEOUS  STATE.  The  molecules  which  break  loose  from  the  surface 
of  the  water  as  it  evaporates  form  a  gas — water-vapour  or  steam.  A  gas 
consists  of  a  vast  number  of  molecules  which  fly  about  entirely  independ- 
ently of  one  another,  except  at  the  rare  instants  at  which  two  collide, 
and  so  interfere  with  each  other's  motion.  The  extent  to  which  the  mole- 
cules interfere  with  one  another  must  obviously  depend  on  their  sizes; 


the  larger  they  are,  the  more  frequent  their  collisions  will  be,  and  the 
more  they  will  interfere  with  one  another's  motion.  Actually  the  extent 
of  this  interference  provides  the  best  means  of  estimating  the  sizes  of 
molecules.  They  prove  to  be  exceedingly  small,  being  for  the  most  part 
about  a  hundred-millionth  of  an  inch  in  diameter,  and,  as  a  general  rule, 
the  simpler  molecules  have  the  smaller  diameters,  as  we  might  perhaps 
have  anticipated.  The  molecule  of  water  has  a  diameter  of  1.8  hundred- 
millionths  of  an  inch  (4.6  X  io~8  cm.),  while  that  of  the  simpler  hydro- 
gen molecule  is  only  just  over  a  hundred-millionth  of  an  inch  (2.7  X 
io"8  cm.).  The  fact  that  a  number  of  different  lines  of  investigation  all 
assign  the  same  diameters  to  these  molecules  provides  an  excellent  proof 
of  the  reality  of  their  existence. 

As  molecules  are  so  exceedingly  small,  they  must  also  be  exceedingly 
numerous.  A  pint  of  water  contains  1.89  X  io25  molecules,  each  weighing 
i. 06  X  io~24  ounce.  If  these  molecules  were  placed  end  to  end,  they 
would  form  a  chain  capable  of  encircling  the  earth  over  200  million  times. 
If  they  were  scattered  over  the  whole  land  surface  of  the  earth,  there 
would  be  nearly  100  million  molecules  to  every  square  inch  of  land.  If 
we  think  of  the  molecules  as  tiny  seeds,  the  total  amount  of  seed  needed 
to  sow  the  whole  earth  at  the  rate  of  100  million  molecules  to  the  square 
inch  could  be  put  into  a  pint  pot. 

These  molecules  move  with  very  high  speeds;  the  molecules  which 
constitute  the  ordinary  air  of  an  ordinary  room  move  with  an  average 
speed  of  about  500  yards  a  second.  This  is  roughly  the  speed  of  a  rifle- 
bullet,  and  is  rather  more  than  the  ordinary  speed  of  sound.  As  we  are 
familiar  with  this  latter  speed  from  everyday  experience,  it  is  easy  to  form 
some  conception  of  molecular  speeds  in  a  gas.  It  is  not  a  mere  accident 
that  molecular  speeds  are  comparable  with  the  speed  of  sound.  Sound 
is  a  disturbance  which  one  molecule  passes  on  to  another  when  it  collides 
with  it,  rather  like  relays  of  messengers  passing  a  message  on  to  one 
another,  or  Greek  torch-bearers  handing  on  their  lights.  Between  collisions 
the  message  is  carried  forward  at  exactly  the  speed  at  which  the  molecules 
travel.  If  these  all  travelled  with  precisely  the  same  speed  and  in  precisely 
the  same  direction,  the  sound  would  of  course  travel  with  just  the  speed 
of  the  molecules.  But  many  of  them  travel  on  oblique  courses,  so  that 
although  the  average  speed  of  individual  molecules  in  ordinary  air  is 
about  500  yards  a  second,  the  net  forward  velocity  of  the  sound  is  only 
about  370  yards  a  second. 

At  high  temperatures  the  molecules  may  have  even  greater  speeds;  the 
molecules  of  steam  in  a  boiler  may  move  at  1000  yards  a  second. 

It  is  the  high  speed  of  molecular  motion  that  is  responsible  for  the 


great  pressure  exerted  by  a  gas;  any  surface  in  contact  with  ordinary  air 
is  exposed  to  a  hail  of  molecules  each  moving  with  the  speed  of  a  rifle- 
bullet.  With  each  breath  we  take,  swarms  of  millions  of  millions  of 
millions  of  molecules  enter  our  bodies,  each  moving  at  about  500  yards  a 
second,  and  nothing  but  their  incessant  hammering  on  the  walls  of  our 
lungs  keeps  our  chests  from  collapsing.  To  take  another  instance,  the 
piston  in  a  locomotive  cylinder  is  bombarded  by  about  14  X  io28  mole- 
cules every  second,  each  moving  at  about  800  yards  a  second.  This  inces- 
sant fusillade  of  innumerable  tiny  bullets  urges  the  piston  forward  in  the 
cylinder,  and  so  propels  the  train.  .  .  . 


In  the  gaseous  state,  each  separate  molecule  retains  all  the  chemical 
properties  of  the  solid  or  liquid  substance  from  which  it  originated; 
molecules  of  steam,  for  instance,  moisten  salt  or  sugar,  or  combine  with 
thirsty  substances  such  as  unslaked  lime  or  potassium  chloride,  just  as 
water  does. 

Is  it  possible  to  break  up  the  molecules  still  further?  Lucretius  and  his 
predecessors  would,  of  course,  have  said:  "No."  A  simple  experiment, 
which,  however,  was  quite  beyond  their  range,  will  speedily  shew  that 
they  were  wrong. 

On  sliding  the  two  wires  of  an  ordinary  electric  bell  circuit  into  a 
tumbler  of  water,  down  opposite  sides,  bubbles  of  gas  will  be  found  to 
collect  on  the  wires,  and  chemical  examination  shews  that  the  two  lots  of 
gas  have  entirely  different  properties.  They  cannot,  then,  both  be  water- 
vapour,  and  in  point  of  fact  neither  of  them  is;  one  proves  to  be  hydrogen 
and  the  other  oxygen.  There  is  found  to  be  twice  as  much  hydrogen  as 
oxygen,  whence  we  conclude  that  the  electric  current  has  broken  up  each 
molecule  of  water  into  two  parts  of  hydrogen  and  one  of  oxygen.  These 
smaller  units  into  which  a  molecule  is  broken  are  called  "atoms."  Each 
molecule  of  water  consists  of  two  atoms  of  hydrogen  (H)  and  one  atom 
of  oxygen  (O) ;  this  is  expressed  in  its  chemical  formula  HbO. 

All  the  innumerable  substances  which  occur  on  earth — shoes,  ships, 
sealing-wax,  cabbages,  kings,  carpenters,  walruses,  oysters,  everything  we 
can  think  of — can  be  analysed  into  their  constituent  atoms,  either  in  this 
or  in  other  ways.  It  might  be  thought  that  a  quite  incredible  number  of 
different  kinds  of  atoms  would  emerge  from  the  rich  variety  of  sub- 
stances we  find  on  earth.  Actually  the  number  is  quite  small.  The  same 
atoms  turn  up  again  and  again,  and  the  great  variety  of  substances  we 
find  on  earth  results,  not  from  any  great  variety  of  atoms  entering  into 
their  composition,  but  from  the  great  variety  of  ways  in  which  a  few 


types  of  atoms  can  be  combined — just  as  in  a  colour-print  three  colours 
can  be  combined  so  as  to  form  almost  all  the  colours  we  meet  in  nature, 
not  to  mention  other  weird  hues  such  as  never  were  on  land  or  sea. 

Analysis  of  all  known  terrestrial  substances  has,  so  far,  revealed  only 
90  different  kinds  of  atoms.  Probably  92  exist,  there  being  reasons  for 
thinking  that  two,  or  possibly  even  more,  still  remain  to  be  discovered. 
Even  of  the  90  already  known,  the  majority  are  exceedingly  rare,  most 
common  substances  being  formed  out  of  the  combinations  of  about  14 
different  atoms,  say  hydrogen  (H),  carbon  (C),  nitrogen  (N),  oxygen 
(O),  sodium  (Na),  magnesium  (Mg),  aluminum  (Al),  silicon  (Si), 
phosphorus  (P),  sulphur  (S),  chlorine  (Cl),  potassium  (K),  calcium 
(Ca),  and  iron  (Fe). 

In  this  way,  the  whole  earth,  with  its  endless  diversity  of  substances,  is 
found  to  be  a  building  built  of  standard  bricks — the  atoms.  And  of  these 
only  a  few  types,  about  14,  occur  at  all  abundantly  in  the  structure,  the 
others  appearing  but  rarely. 

SPECTROSCOPY.  Just  as  a  bell  struck  with  a  hammer  emits  a  char- 
acteristic note,  so  every  atom  put  in  a  flame  or  in  an  electric  arc  or  discharge- 
tube,  emits  a  characteristic  light,  which  the  spectroscope  will  resolve  into 
its  separate  constituents. 

The  spectrum  of  sunlight  discloses  the  chemical  composition  of  the 
solar  atmosphere,  and  here  again  we  still  find  the  same  types  of  atoms 
as  on  earth,  and  no  others.  With  a  few  quite  unimportant  exceptions, 
every  line  in  the  sun's  spectrum  can  be  identified  as  originating  from 
some  type  of  atom  already  known  on  earth.  Of  the  fifteen  metals  which 
are  believed  to  be  commonest  in  the  sun's  atmosphere,  seven,  which 
account  for  no  less  than  96  per  cent,  of  the  whole,  figure  in  our  list  of  the 
fourteen  elements  which  are  commonest  on  earth.  Actually  they  are 
precisely  the  seven  principal  constituents  of  terrestrial  rocks,  although 
their  relative  proportions  are  different  on  the  sun  and  earth. 

Thus,  broadly  speaking  the  same  atoms  occur  in  the  sun's  atmosphere 
as  on  earth,  and  the  same  is  true  of  the  atmospheres  of  the  stars.  It  is 
tempting  to  jump  to  the  generalisation  that  the  whole  universe  is  built 
solely  of  the  90  or  92  types  of  atoms  found  on  earth,  but  at  present  there 
is  no  justification  for  this.  The  light  we  receive  from  the  sun  and  stars 
comes  only  from  the  outermost  layers  of  their  surfaces,  and  so  conveys  no 
information  at  all  as  to  the  types  of  atoms  to  be  found  in  the  stars' 
interiors.  Indeed  we  have  no  knowledge  of  the  types  of  atoms  which 
occur  in  the  interior  of  our  own  earth. 

THE  STRUCTURE  OF  THE  ATOM.  Until  quite  recently,  atoms  were 
regarded  as  the  permanent  bricks  of  which  the  whole  universe  was  built. 


All  the  changes  of  the  universe  were  supposed  to  amount  to  nothing 
more  drastic  than  a  re-arrangement  of  permanent  indestructible  atoms; 
like  a  child's  box  of  bricks,  these  built  many  buildings  in  turn.  The  story 
of  twentieth-century  physics  is  primarily  the  story  of  the  shattering  of 
this  concept. 

It  was  towards  the  end  of  the  last  century  that  Crookes,  Lenard,  and 
above  all,  Sir  J.  J.  Thomson  first  began  to  break  up  the  atom.  The  struc- 
tures which  had  been  deemed  the  unbreakable  bricks  of  the  universe  for 
more  than  2000  years,  were  suddenly  shown  to  be  very  susceptible  to 
having  fragments  chipped  off.  A  mile-stone  was  reached  in  1897,  when 
Thomson  shewed  that  these  fragments  were  identical  no  matter  what 
type  of  atom  they  came  from;  they  were  of  equal  weight  and  they  carried 
equal  charges  of  negative  electricity.  On  account  of  this  last  property  they 
were  called  "electrons."  The  atom  cannot,  however,  be  built  up  of  elec- 
trons and  nothing  else,  for  as  each  electron  carries  a  negative  charge  of 
electricity,  a  structure  which  consisted  of  nothing  but  electrons  would  also 
carry  a  negative  charge.  Two  negative  charges  of  electricity  repel  one 
another,  as  also  do  two  positive  charges,  while  two  charges,  one  of  positive 
and  one  of  negative  electricity,  attract  one  another.  This  makes  it  easy 
to  determine  whether  any  body  or  structure  carries  a  positive  or  a  negative 
charge  of  electricity,  or  no  charge  at  all.  Observation  shews  that  a  com- 
plete atom  carries  no  charge  at  all,  so  that  somewhere  in  the  atom  there 
must  be  a  positive  charge  of  electricity,  of  amount  just  sufficient  to 
neutralise  the  combined  negative  charges  of  all  the  electrons. 

In  1911  experiments  by  Sir  Ernest  Rutherford  and  others  revealed  the 
architecture  of  the  atom,  in  its  main  lines  at  least.  As  we  shall  soon  see, 
nature  herself  provides  an  endless  supply  of  small  particles  charged  with 
positive  electricity,  and  moving  with  very  high  speeds,  in  the  a-particles 
shot  off  from  radio-active  substances.  Rutherford's  method  was  in  brief 
to  fire  these  into  atoms  and  observe  the  result.  And  the  surprising  result 
he  obtained  was  that  the  vast  majority  of  these  bullets  passed  straight 
through  the  atom  as  though  it  simply  did  not  exist.  It  was  like  shooting 
at  a  ghost. 

Yet  the  atom  was  not  all  ghostly.  A  tiny  fraction — perhaps  one  in 
10,000 — of  the  bullets  were  deflected  from  their  courses  as  if  they  had  met 
something  very  substantial  indeed.  A  mathematical  calculation  shewed 
that  these  obstacles  could  only  be  the  missing  positive  charges  of  the 

A  detailed  study  of  the  paths  of  these  projectiles  proved  that  the  whole 
positive  charge  of  an  atom  must  be  concentrated  in  a  single  very  small 
space,  having  dimensions  of  the  order  of  only  a  millionth  of  a  millionth  of 


an  inch.  In  this  way,  Rutherford  was  led  to  propound  the  view  of  atomic 
structure  which  is  generally  associated  with  his  name.  He  supposed  the 
chemical  properties  and  nature  of  the  atom  to  reside  in  a  weighty,  but 
excessively  minute,  central  "nucleus"  carrying  a  positive  charge  of  elec- 
tricity, around  which  a  number  of  negatively  charged  electrons  described 
orbits.  He  had  to  suppose  that  the  electrons  were  in  motion  in  the  atom, 
otherwise  the  attraction  of  positive  for  negative  electricity  would  immedi- 
ately draw  them  into  the  central  nucleus — just  as  gravitational  attraction 
would  cause  the  earth  to  fall  into  the  sun,  were  it  not  for  the  earth's 
orbital  motion.  In  brief,  Rutherford  supposed  the  atom  to  be  constructed 
like  the  solar  system,  the  heavy  central  nucleus  playing  the  part  of  the 
sun  and  the  electrons  acting  the  parts  of  the  planets. 

The  modern  theory  of  wave-mechanics  casts  doubt  on  some  at  least 
of  these  concepts — perhaps  on  all,  although  this  is  still  in  doubt.  Thus  it 
may  prove  necessary  ro  discard  many  or  all  of  them  before  long.  Yet 
Rutherford's  concepts  provide  a  simple  and  easily  visualised  picture  of 
the  atom,  whereas  the  theory  of  wave-mechanics  has  not  yet  been  able 
to  provide  a  picture  at  all.  For  this  reason  we  shall  continue  to  describe 
the  atom  in  terms  of  Rutherford's  picture. 

According  to  this  picture,  the  electrons  are  supposed  to  move  round 
the  nucleus  with  just  the  speeds  necessary  to  save  them  from  being 
drawn  into  it,  and  these  speeds  prove  to  be  terrific,  the  average  electron 
revolving  around  its  nucleus  several  thousand  million  million  times  every 
second,  with  a  speed  of  hundreds  of  miles  a  second.  Thus  the  smallness 
of  their  orbits  does  not  prevent  the  electrons  moving  with  higher  orbital 
speeds  than  the  planets,  or  even  the  stars  themselves. 

By  clearing  a  space  around  the  central  nucleus,  and  so  preventing  other 
atoms  from  coming  too  near  to  it,  these  electronic  orbits  give  size  to  the 
atom.  The  volume  of  space  kept  clear  by  the  electrons  is  enormously 
greater  than  the  total  volume  of  the  electrons;  roughly,  the  ratio  of 
volumes  is  that  of  the  battlefield  to  the  bullets.  The  atom  has  about 
100,000  times  the  diameter,  and  so  about  a  thousand  million  million  times 
the  volume,  of  a  single  electron.  The  nucleus,  although  it  generally  weighs 
3000  or  4000  times  as  much  as  all  the  electrons  in  the  atom  together,  is  at 
most  comparable  in  size  with,  and  may  be  even  smaller  than,  a  single 

We  know  the  extreme  emptiness  of  astronomical  space.  Choose  a  point 
in  space  at  random,  and  the  odds  against  its  being  occupied  by  a  star  are 
enormous.  Even  the  solar  system  consists  overwhelmingly  of  empty  space; 
choose  a  spot  inside  the  solar  system  at  random,  and  there  are  still 
immense  odds  against  its  being  occupied  by  a  planet  or  even  by  a  comet, 


meteorite  or  smaller  body.  And  now  we  see  that  this  emptiness  extends 
also  to  the  space  of  physics.  Even  inside  the  atom  we  choose  a  point  at 
random,  and  the  odds  against  there  being  anything  there  are  immense; 
they  are  of  the  order  of  at  least  millions  of  millions  to  one.  Six  specks 
of  dust  inside  Waterloo  Station  represent — or  rather  over-represent — the 
extent  to  which  space  is  crowded  with  stars.  In  the  same  way  a  few 
wasps — six  for  the  atom  of  carbon — flying  around  in  Waterloo  Station 
will  represent  the  extent  to  which  the  atom  is  crowded  with  electrons — 
all  the  rest  is  emptiness.  As  we  pass  the  whole  structure  of  the  universe 
under  review,  from  the  giant  nebulae  and  the  vast  interstellar  and  inter- 
nebular  spaces  down  to  the  tiny  structure  of  the  atom,  little  but  vacant 
space  passes  before  our  mental  gaze.  We  live  in  a  gossamer  universe; 
pattern,  plan  and  design  are  there  in  abundance,  but  solid  substance  is 

ATOMIC  NUMBERS.  The  number  of  elecrons  which  fly  round  in  orbits 
in  an  atom  is  called  the  "atomic  number"  of  the  atom.  Atoms  of  all 
atomic  numbers  from  i  to  92  have  been  found,  except  for  two  missing 
numbers  85  and  87.  As  already  mentioned,  it  is  highly  probable  that  these 
also  exist,  and  that  there  are  92  "elements"  whose  atomic  numbers  occupy 
the  whole  range  of  atomic  numbers  from  i  to  92  continuously. 

The  atom  of  atomic  number  unity  is  of  course  the  simplest  of  all.  It  is 
the  hydrogen  atom,  in  which  a  solitary  electron  revolves  around  a  nucleus 
whose  charge  of  positive  electricity  is  exactly  equal  in  amount,  although 
opposite  in  sign,  to  the  charge  on  the  negative  electron. 

Next  comes  the  helium  atom  of  atomic  number  2,  in  which  two  elec- 
trons revolve  about  a  nucleus  which  has  four  times  the  weight  of  the 
hydrogen  nucleus  although  carrying  only  twice  its  electric  charge.  After 
this  comes  the  lithium  atom  of  atomic  number  3,  in  which  three  electrons 
revolve  around  a  nucleus  having  six  times  the  weight  of  the  hydrogen 
atom  and  three  times  its  charge.  And  so  it  goes  on,  until  we  reach  ura- 
nium, the  heaviest  of  all  atoms  known  on  earth,  which  has  92  electrons 
describing  orbits  about  a  nucleus  of  238  times  the  weight  of  the  hydrogen 


While  physical  science  was  still  engaged  in  breaking  up  the  atom  into 
its  component  factors,  it  made  the  further  discovery  that  the  nuclei  them- 
selves were  neither  permanent  nor  indestructible.  In  1896  Becquerel  had 
found  that  various  substances  containing  uranium  possessed  the  remark- 
able property,  as  it  then  appeared,  of  spontaneously  affecting  photographic 
plates  in  their  vicinity.  This  observation  led  to  the  discoverv  of  a  new 


property  of  matter,  namely  radio-activity.  All  the  results  obtained  from 
the  study  of  radio-activity  in  the  few  following  years  were  co-ordinated 
in  the  hypothesis  of  "spontaneous  disintegration"  which  Rutherford  and 
Soddy  advanced  in  1903.  According  to  this  hypothesis  in  its  present  form, 
radio-activity  indicates  a  spontaneous  break-up  of  the  nuclei  of  the  atoms 
of  radio-active  substances.  These  atoms  are  so  far  from  being  permanent 
and  indestructible  that  their  very  nuclei  crumble  away  with  the  mere 
lapse  of  time,  so  that  what  was  once  the  nucleus  of  a  uranium  atom  is 
transformed,  after  sufficient  time,  into  the  nucleus  of  a  lead  atom. 

The  process  of  transformation  is  not  instantaneous;  it  proceeds  grad- 
ually and  by  distinct  stages.  During  its  progress,  three  types  of  product  are 
emitted,  which  are  designated  a-rays,  (3-rays,  and  y-rays. 

These  were  originally  described  indiscriminately  as  rays  because  all 
three  were  found  to  have  the  power  of  penetrating  through  a  certain 
thickness  of  air,  metal,  or  other  substance.  It  was  not  until  later  that  their 
true  nature  was  discovered.  It  is  well  known  that  magnetic  forces,  such 
as,  for  instance,  occur  in  the  space  between  the  poles  of  a  magnet,  cause 
a  moving  particle  charged  with  electricity  to  deviate  from  a  straight 
course;  the  particle  deviates  in  one  direction  or  the  other  according  as 
it  is  charged  with  positive  or  negative  electricity.  On  passing  the  various 
rays  emitted  by  radio-active  substances  through  the  space  between  the 
poles  of  a  powerful  magnet,  the  a-rays  were  found  to  consist  of  particles 
charged  with  positive  electricity,  and  the  P-rays  to  consist  of  particles 
charged  with  negative  electricity.  But  the  most  powerful  magnetic  forces 
which  could  be  employed  failed  to  cause  the  slightest  deviation  in  the 
paths  of  the  y-rays,  from  which  it  was  concluded  that  either  the  y-rays 
were  not  material  particles  at  all,  or  that,  if  they  were,  they  carried  no 
electric  charges.  The  former  of  these  alternatives  was  subsequently  proved 
to  be  the  true  one. 

a-p ARTICLES.  The  positively  charged  particles  which  constitute  a-rays 
are  generally  described  as  a-particles.  In  1909  Rutherford  and  Royds 
allowed  a-particles  to  penetrate  through  a  thin  glass  wall  of  less  than  a 
hundredth  of  a  millimetre  in  thickness  into  a  chamber  from  which  they 
could  not  escape — a  sort  of  mouse-trap  for  a-particles.  After  the  process 
had  continued  for  a  long  time,  the  final  result  was  not  an  accumulation 
of  a-particles  but  an  accumulation  of  the  gas  helium,  the  next  simplest 
gas  after  hydrogen.  In  this  way  it  was  established  that  the  positively 
charged  a-particles  are  simply  nuclei  of  helium  atoms;  the  a-particles, 
being  positively  charged,  had  attracted  negatively  charged  electrons  to 
themselves  out  of  the  walls  of  the  chamber  and  the  result  was  a  collection 
of  complete  helium  atoms. 


The  a-particles  move  with  enormous  speeds,  which  depend  upon  the 
nature  of  the  radio-active  substance  from  which  they  have  been  shot  out. 
The  fastest  particles  of  all  move  with  a  speed  of  12,800  miles  a  second; 
even  the  slowest  have  a  speed  of  8800  miles  a  second,  which  is  about 
30,000  times  the  ordinary  molecular  velocity  in  air.  Particles  moving  with 
such  speeds  as  these  knock  all  ordinary  molecules  out  of  their  way;  this 
explains  the  great  penetrating  power  of  the  a-rays. 

(3-p ARTICLES.  By  examining  the  extent  to  which  their  motion  was 
influenced  by  magnetic  forces,  the  P-rays  were  found  to  consist  of  nega- 
tively charged  electrons,  exactly  similar  to  those  which  surround  the 
nucleus  in  all  atoms.  As  an  a-particle  carries  a  positive  charge  equal  in 
amount  to  that  of  two  electrons,  an  atom  which  has  ejected  an  a-particle 
is  left  with  a  deficiency  of  positive  charge,  or  what  comes  to  the  same 
thing,  with  a  negative  charge,  equal  to  that  of  two  electrons.  Consequently 
it  is  natural,  and  indeed  almost  inevitable,  that  the  ejections  of  a-particles 
should  alternate  with  an  ejection  of  negatively  charged  electrons,  in  the 
proportion  of  one  a-particle  to  two  electrons,  so  that  the  balance  of  posi- 
tive and  negative  electricity  in  the  atom  may  be  maintained.  The  (3-parti- 
cles  move  with  even  greater  speeds  than  the  a-particles,  many  approaching 
to  within  a  few  per  cent,  of  the  velocity  of  light  (186,000  miles  a 
second).  .  .  . 

Y-RAYS.  As  has  already  been  mentioned,  the  y-rays  are  not  material 
particles  at  all;  they  prove  to  be  merely  radiation  of  a  very  special  kind. 

Thus  the  break-up  of  a  radio-active  atom  may  be  compared  to  the 
discharge  of  a  gun;  the  a-particle  is  the  shot  fired,  the  ^-particles  are  the 
smoke,  and  the  y-rays  are  the  flash.  The  atom  of  lead  which  finally 
remains  is  the  unloaded  gun,  and  the  original  radio-active  atom,  of 
uranium  or  what  not,  was  the  loaded  gun.  And  the  special  peculiarity  of 
radio-active  guns  is  that  they  go  of?  spontaneously  and  of  their  own 
accord.  All  attempts  to  pull  the  trigger  have  so  far  failed,  or  at  least  have 
led  to  inconclusive  results;  we  can  only  wait,  and  the  gun  will  be  found 
to  fire  itself  in  time.  .  .  . 

In  1920,  Rutherford,  using  radio-active  atoms  as  guns,  fired  a-particles 
at  light  atoms  and  found  that  direct  hits  broke  up  their  nuclei.  There  is, 
however,  found  to  be  a  significant  difference  between  the  spontaneous 
disintegration  of  the  heavy  radio-active  atoms  and  the  artificial  disintegra- 
tion of  the  light  atoms;  in  the  former  case,  apart  from  the  ever-present 
P-rays  and  y-rays,  only  a-particles  are  ejected,  while  in  the  latter  case 
a-particles  were  not  ejected  at  all,  but  particles  of  only  about  a  quarter 
their  weight,  which  proved  to  be  identical  with  the  nuclei  of  hydrogen 
atoms.  .  .  . 


ISOTOPES.  Two  atoms  have  the  same  chemical  properties  if  the  charges 
of  positive  electricity  carried  by  their  nuclei  are  the  same.  The  amount  of 
this  charge  fixes  the  number  of  electrons  which  can  revolve  around  the 
nucleus,  this  number  being  of  course  exactly  that  needed  to  neutralise 
the  electric  field  of  the  nucleus,  and  this  in  turn  fixes  the  atomic  number 
of  the  element.  And  it  has  for  long  been  known  that  the  weights  of  all 
atoms  are,  to  a  very  close  approximation,  multiples  of  a  single  definite 
weight.  This  unit  weight  is  approximately  equal  to  the  weight  of  the 
hydrogen  atom,  but  is  more  nearly  equal  to  a  sixteenth  of  the  weight 
of  the  oxygen  atom.  The  weight  of  any  type  of  atom,  measured  in  terms 
of  this  unit,  is  called  the  "atomic  weight"  of  the  atom. 

It  used  to  be  thought  that  a  mass  of  any  single  chemical  element,  such 
as  mercury  or  xenon,  consisted  of  entirely  similar  atoms,  every  one  o£ 
which  had  not  only  the  same  atomic  number  but  also  the  same  atomic 
weight.  But  Dr.  Aston  has  shewn  very  convincingly  that  atoms  of  the 
same  chemical  element,  say  neon  or  chlorine,  may  have  nuclei  of  a  great 
many  different  weights.  The  various  forms  which  the  atoms  of  the  same 
chemical  element  can  assume  are  known  as  isotopes  being  of  course 
distinguished  by  their  different  weights. 

These  weights  are  much  nearer  to  whole  numbers  than  were  the  old 
"atomic"  weights  of  the  chemists.  For  instance  the  atomic  weight  of 
chlorine  used  to  be  given  as  35-5,  and  this  was  taken  to  mean  that  chlorine 
consisted  of  a  mixture  of  atoms  each  35-5  times  as  massive  as  the  hydrogen 
atom.  Aston  finds  that  chlorine  consists  of  a  mixture  of  atoms  of  atomic 
weights  35  and  37  (or  more  accurately  34-983  and  36-980),  the  former  being 
approximately  three  times  as  plentiful  as  the  latter.  In  the  same  way  a 
mass  of  mercury,  of  which  the  mean  atomic  weight  is  about  200-6,  is 
found  to  be  a  mixture  of  seven  kinds  of  atoms  of  atomic  weights  196,  198, 
199,  200,  201,  202,  204.  Tin  is  a  mixture  of  no  fewer  than  eleven  isotopes — 
112,  114,  115,  116,  117,  118,  119,  120,  121,  122,  124. 

PROTONS  AND  ELECTRONS.  When  the  presence  of  isotopes  is  taken  into 
account,  the  atomic  weights  of  all  atoms  prove  to  be  far  nearer  to  integral 
numbers  than  had  originally  been  thought.  This,  in  conjunction  with 
Rutherford's  artificial  disintegration  of  atomic  nuclei,  led  to  the  general 
acceptance  of  the  hypothesis  that  the  whole  universe  is  built  up  of  only 
two  kinds  of  ultimate  bricks,  namely,  electrons  and  protons.  Each  proton 
carries  a  positive  charge  of  electricity  exactly  equal  in  amount  to  the 
negative  charge  carried  by  an  electron,  but  has  about  1847  times  the  weight 
of  the  electron.  Protons  are  supposed  to  be  identical  with  the  nucleus 
of  the  hydrogen  atom,  all  other  nuclei  being  composite  structures  in  which 
both  protons  and  electrons  are  closely  packed  together.  For  instance,  the 


nucleus  of  the  helium  atom,  the  a-particle,  consists  of  four  protons  and 
two  electrons,  these  giving  it  approximately  four  times  the  weight  of  the 
hydrogen  atom,  and  a  resultant  charge  equal  to  twice  that  of  the  nucleus 
of  the  hydrogen  atom. 

NEUTRONS.  Until  quite  recently  this  hypothesis  was  believed  to  give 
a  satisfactory  and  complete  account  of  the  structure  of  matter.  Then  in 
1931  two  German  physicists,  Bothe  and  Becker,  bombarding  the  light 
elements  beryllium  and  boron  with  the  very  rapid  a-particles  emitted  by 
polonium,  obtained  a  new  and  very  penetrating  radiation  which  they 
were  at  first  inclined  to  interpret  as  a  kind  of  y-radiation.  Subsequently 
Dr.  Chad  wick  of  Cambridge  shewed  that  it  possessed  properties  which 
were  inconstant  with  this  interpretation  and  made  it  clear  that  the  radia- 
tion consists  of  material  objects  of  a  type  hitherto  unknown  to  science. 
To  the  greatest  accuracy  of  which  the  experiments  permit  these  objects 
are  found  to  have  the  same  mass  as  the  hydrogen  atom,  while  their  very 
high  penetrating  power  shews  that  if  they  have  any  electric  charge  at  all, 
it  can  only  be  a  minute  fraction  at  most  of  the  charge  of  the  electron. 

Thus  it  seems  likely  that  the  radiation  consists  of  uncharged  particles 
of  the  same  mass  as  the  proton — something  quite  new  in  a  world  which 
until  recently  was  believed  to  consist  entirely  of  charged  particles.  Chad- 
wick  describes  these  new  particles  as  "neutrons."  Whether  they  are 
themselves  fundamental  constituents  of  matter  or  not  remains  to  be  seen. 
Chadwick  has  suggested  that  they  may  be  composite  structures,  each 
consisting  of  a  proton  and  electron  in  such  close  combination  that  they 
penetrate  matter  almost  as  freely  as  though  they  had  no  size  at  all.  On  the 
other  hand  Heisenberg  has  considered  the  possibility  that  the  neutron 
may  be  fundamental,  the  nucleus  of  an  atom  being  built  up  solely  of 
positively  charged  protons  and  uncharged  neutrons,  while  the  negative 
electrons  are  confined  to  the  regions  outside  the  nucleus.  On  this  view 
there  are  just  as  many  protons  in  the  nucleus  as  there  are  electrons  outside 
the  nucleus,  the  number  of  each  being  the  atomic  number  of  the  element, 
while  the  excess  of  mass  needed  to  make  up  the  atomic  weight  is  provided 
by  the  inclusion  of  the  requisite  number  of  neutrons  in  the  nucleus. 
Isotopes  of  the  same  element  differ  of  course  merely  in  having  different 
numbers  of  neutrons  in  their  nuclei. 

Rutherford  and  other  physicists  have  considered  the  further  possibility 
that  other  kinds  of  neutrons,  with  double  the  mass  of  the  hydrogen  atom, 
may  also  occur  in  atomic  nuclei,  a  hypothesis  for  which  there  seems  to 
be  considerable  observational  support. 

POSITIVE  ELECTRONS.  Even  more  revolutionary  discoveries  were  to 
come.  A  few  years  ago  it  seemed  a  piece  of  extraordinary  good  luck  that 
in  the  a-particles  nature  herself  had  provided  projectiles  of  sufficient 


shattering  power  to  smash  up  the  nucleus  of  the  atom  and  disclose  its 
secrets  to  the  observation  of  the  physicist.  More  recently  nature  has  been 
found  to  provide  yet  more  shattering  projectiles  in  the  cosmic  radiation 
which  continually  bombards  the  surface  of  the  earth — probably  from 
outer  space.  This  radiation  has  such  a  devastating  effect  on  the  atomic 
nuclei  that  it  is  difficult  to  make  much  of  the  resulting  collection  of  frag- 
ments. It  is,  however,  always  possible  to  examine  any  debris,  no  matter 
how  involved,  by  noticing  how  the  constituent  particles  move  when  acted 
on  by  magnetic  forces. 

In  1932  C.  D.  Anderson  made  observations  which  suggested  that  this 
debris  contained,  among  other  ingredients,  particles  having  the  same 
positive  charge  as  the  proton,  but  a  mass  only  comparable  with,  and  pos- 
sibly equal  to,  that  of  the  electron.  The  existence  of  such  particles  has  been 
confirmed  by  Blackett  and  Occhialini  at  Cambridge.  The  new  particles 
may  well  be  described  as  positively  charged  electrons,  and  so  have  been 
named  "positrons." 

As  these  new  particles  are  believed  to  emerge  from  atomic  nuclei,  it 
would  seem  plausible  to  suppose  that  they  must  be  normal  constituents 
of  the  nuclei.  Yet  the  recent  discovery  of  the  neutron  suggests  other  pos- 

We  have  already  mentioned  the  hypothesis,  advocated  by  Heisenberg 
and  others,  that  the  nucleus  consists  solely  of  neutrons  and  protons.  Ander- 
son has  suggested  that  the  proton  may  not  be  a  fundamental  unit  in  the 
structure  of  matter,  but  may  consist  of  a  positron  and  a  neutron  in  com- 
bination. Every  nucleus  would  then  contain  only  neutrons  and  positrons, 
and  the  positrons  could  be  driven  out  by  bombardment  in  the  ordinary 

The  objection  to  this  view  is  that  the  debris  of  the  nuclei  shattered  by 
cosmic  radiation  is  found  to  contain  electrons  as  well  as  positrons,  the 
electrons  emerging,  so  far  as  can  be  seen,  from  the  same  atomic  nuclei  as 
the  positrons.  This  has  led  Blackett  and  Occhialini  to  propound  the 
alternative  hypothesis  that  the  electrons  and  positrons  are  born  in  pairs  as 
the  result  of  the  processes  of  bombardment  and  disintegration  of  atomic 
nuclei.  At  first  this  may  seem  a  flagrant  violation  of  all  our  views  as  to  the 
permanence  of  matter,  but  we  shall  see  shortly  that  it  is  entirely  in  accord 
with  the  present  trend  of  physics. 

It  seems  fairly  certain  that  the  positron  has  at  most  but  a  temporary 
existence.  For  positrons  do  not  appear  to  be  associated  with  matter  under 
normal  conditions,  although  they  ought  to  abound  if  they  were  being 
continually  produced  out  of  nuclei  at  anything  like  the  rate  which  the 
observations  of  Blackett  and  Occhialini  seem  to  indicate.  They  might  of 


course  rapidly  disappear  from  view  through  entering  into  combination 
with  negatively  charged  particles  to  form  some  sort  of  permanent  stable 
structure,  but  it  seems  more  probable,  as  Blackett  and  Occhialini  them- 
selves suggest,  that  they  disappear  from  existence  altogether  by  combining 
with  negative  electrons.  Just  as  a  pair  of  electrons — one  positively  charged 
and  one  negatively  charged — can  be  born  out  of  nothing  but  energy,  so 
they  can  die  in  one  another's  arms  and  leave  nothing  but  energy  behind. 
We  shall  discuss  the  underlying  physical  mechanism  almost  immediately. 
Before  the  existence  of  the  positron  had  been  observed,  or  even  suspected 
experimentally,  Professor  Dirac  of  Cambridge  had  propounded  a  mathe- 
matical theory  which  predicted  not  only  the  existence  of  the  positron,  but 
also  the  way  in  which  it  ought  to  behave.  Dirac's  theory  is  too  abstrusely 
mathematical  to  be  explained  here,  but  it  predicts  that  a  shower  of  posi- 
trons ought  gradually  to  fade  away  by  spontaneous  combination  with 
negative  electrons,  following  the  same  law  of  decay  as  radio-active  sub- 
stances. And  the  average  life  of  a  positron  is  predicted  to  be  one  of  only 
a  few  millionths  of  a  second,  which  amply  explains  why  the  positron  can 
live  long  enough  to  be  photographed  in  a  condensation  chamber,  but  not 
long  enough  to  shew  its  presence  elsewhere  in  the  universe. 


We  have  so  far  discussed  only  the  material  constituents  of  matter:  we 
have  pictured  the  atom  as  being  built  up  of  some  or  all  of  the  material 
ingredients  which  we  have  described  as  electrons,  protons,  neutrons  and 
positrons.  Yet  this  is  not  the  whole  story.  If  it  were,  every  atom  would 
consist  of  a  certain  number  of  protons  and  neutrons  with  just  sufficient 
electrons  and  positrons  to  make  the  total  electric  charge  equal  to  zero. 
Thus,  apart  from  the  insignificant  weights  of  electrons  and  positrons,  the 
weight  of  every  atom  would  be  an  exact  multiple  of  the  weight  of  a 
hydrogen  atom.  Experiment  shews  this  not  to  be  the  case. 

ELECTROMAGNETIC  ENERGY.  To  get  at  the  whole  truth,  we  have  to 
recognise  that,  in  addition  to  containing  material  electrons  and  protons> 
with  possible  neutrons  and  positrons,  the  atom  contains  yet  a  further 
ingredient  which  we  may  describe  as  electromagnetic  energy.  We  may 
think  of  this,  although  with  something  short  of  absolute  scientific  accuracy, 
as  bottled  radiation. 

If  we  disturb  the  surface  of  a  pond  with  a  stick,  a  series  of  ripples  starts 
from  the  stick  and  travels,  in  a  series  of  ever-expanding  circles,  over  the 
surface  of  the  pond.  As  the  water  resists  the  motion  of  the  stick,  we  have 
to  work  to  keep  the  pond  in  a  state  of  agitation.  The  energy  of  this  work 
is  transformed,  in  part  at  least,  into  the  energy  of  the  ripples.  We  ca,n  see 


that  the  ripples  carry  energy  about  with  them,  because  they  cause  a  floating 
cork  or  a  toy  boat  to  rise  up  against  the  earth's  gravitational  pull.  Thus 
the  ripples  provide  a  mechanism  for  distributing  over  the  surface  of  the 
pond  the  energy  that  we  put  into  the  pond  through  the  medium  of  the 
moving  stick. 

Light  and  all  other  forms  of  radiation  are  analogous  to  water  ripples  or 
waves,  in  that  they  distribute  energy  from  a  central  source.  The  sun's 
radiation  distributes  through  space  the  vast  amount  of  energy  which  is 
generated  inside  the  sun.  We  hardly  know  whether  there  is  any  actual 
wave  motion  in  light  or  not,  but  we  know  that  both  light  and  all  other 
types  of  radiation  are  propagated  in  such  a  form  that  they  have  many  of 
the  properties  of  a  succession  of  waves. 

The  different  colours  of  light  which  in  combination  constitute  sunlight 
can  be  separated  out  by  passing  the  light  through  a  prism,  thus  forming 
a  rainbow  or  "spectrum"  of  colors.  The  separation  can  also  be  effected  by 
an  alternative  instrument,  the  diffraction  grating,  which  consists  merely 
of  a  metal  mirror  with  a  large  number  of  parallel  lines  scratched  evenly 
across  its  surface.  The  theory  of  the  action  of  this  latter  instrument  is 
well  understood;  it  shews  that  actually  the  light  is  separated  into  waves 
of  different  wave-lengths.  (The  wave-length  in  a  system  of  ripples  is  the 
distance  from  the  crest  of  one  ripple  to  that  of  the  next,  and  the  term  may 
be  applied  to  all  phenomena  of  an  undulatory  nature.)  This  proves  that 
different  colours  of  light  are  produced  by  waves  of  different  lengths,  and 
at  the  same  time  enables  us  to  measure  the  lengths  of  the  waves  which 
correspond  to  the  different  colours  of  light. 

These  prove  to  be  very  minute.  The  reddest  light  we  can  see,  which  is 


that  of  longest  wave-length,  has  a  wave-length  of  only —  inch 


(7.5 Xio"5  cm.);  the  most  violet  light  we  can  see  has  a  wave-length  only 
half  of  this,  or  0-000015  inch.  Light  of  all  colours  travels  with  the  same 
uniform  speed  of  186,000  miles,  or  3Xio10  centimetres,  a  second.  The 
number  of  waves  of  red  light  which  pass  any  fixed  point  in  a  second  is 
accordingly  no  fewer  than  four  hundred  million  million.  This  is  called 
the  "frequency"  of  the  light.  Violet  light  has  the  still  higher  frequency 
of  eight  hundred  million  million;  when  we  see  violet  light,  eight  hundred 
million  million  waves  of  light  enter  our  eyes  each  second. 

The  spectrum  of  analysed  sunlight  appears  to  the  eye  to  stretch  from 
red  light  at  one  end  to  violet  light  at  the  other,  but  these  are  not  its  true 
limits.  When  certain  chemical  salts  are  placed  beyond  the  violet  end  of 
the  visible  spectrum,  they  are  found  to  shine  vividly,  shewing  that  even 
out  here  energy  is  being  transported,  although  in  invisible  form.  And 


other  methods  make  it  clear  that  the  same  is  true  out  beyond  the  red  end 
of  the  spectrum.  A  thermometer,  or  other  heat-measuring  instrument, 
placed  here  will  shew  that  energy  is  being  received  here  in  the  form  of 

In  this  way  we  find  that  regions  of  invisible  radiation  stretch  indefi- 
nitely from  both  ends  of  the  visible  spectrum.  From  one  end — the  red — 
we  can  pass  continuously  to  waves  of  the  type  used  for  wireless  transmis- 
sion, which  have  wave-lengths  of  the  order  of  hundreds,  or  even  thousands, 
of  yards.  From  the  violet  end,  we  pass  through  waves  of  shorter  and  ever 
shorter  wave-length — all  the  various  forms  of  ultra-violet  radiation.  At 
wave-lengths  of  from  about  a  hundredth  to  a  thousandth  of  the  wave- 
length of  visible  light,  we  come  to  the  familiar  X-rays,  which  penetrate 
through  inches  of  our  flesh,  so  that  we  can  photograph  the  bones  inside. 
Far  out  even  beyond  these,  we  come  to  the  type  of  radiation  which  con- 
stitutes the  Y-rays,  its  wave-length  being  of  the  order  of 


inch,  or  only  about  a  hundred-thousandth  part  of  the  wave-length  of 
visible  light.  Thus  the  y-rays  may  be  regarded  as  invisible  radiation  of 
extremely  short  wave-length.  We  shall  discuss  the  exact  function  they 
serve  later.  For  the  moment  let  us  merely  remark  that  in  the  first  instance 
they  served  the  extremely  useful  function  of  fogging  BecquereFs  photo- 
graphic plates,  thus  leading  to  the  detection  of  the  radio-active  property 
of  matter. 

It  is  a  commonplace  of  modern  electromagnetic  theory  that  energy  of 
every  kind  carries  weight  about  with  it,  weight  which  is  in  every  sense  as 
real  as  the  weight  of  a  ton  of  coal.  A  ray  of  light  causes  an  impact  on  any 
surface  on  which  it  falls,  just  as  a  jet  of  water  does,  or  a  blast  of  wind,  or 
the  fall  of  a  ton  of  coal;  with  a  sufficiently  strong  light  one  could  knock  a 
man  down  just  as  surely  as  with  the  jet  of  water  from  a  fire  hose.  This  is 
not  a  mere  theoretical  speculation.  The  pressure  of  light  on  a  surface  has 
been  both  detected  and  measured  by  direct  experiment.  The  experiments 
are  extraordinarily  difficult  because,  judged  by  all  ordinary  standards,  the 
weight  carried  by  radiation  is  exceedingly  small;  all  the  radiation  emitted 
from  a  50  horse-power  searchlight  working  continuously  for  a  century 
weighs  only  about  a  twentieth  of  an  ounce. 

It  follows  that  any  substance  which  is  emitting  radiation  must  at  the 
same  time  be  losing  weight.  In  particular,  the  disintegration  of  any  radio- 
active substance  must  involve  a  decrease  of  weight,  since  it  is  accompanied 
by  the  emission  of  radiation  in  the  form  of  Y-rays.  The  ultimate  fate  of  an 
ounce  of  uranium  may  be  expressed  by  the  equation: 


f  0-8653  °unce  lead, 

i  ounce  uranium =«|  0-1345       "      helium, 
[0-0002      "     radiation. 

The  lead  and  helium  together  contain  just  as  many  electrons  and  just 
as  many  protons  as  did  the  original  ounce  of  uranium,  but  their  combined 
weight  is  short  of  the  weight  of  the  original  uranium  by  about  one  part 
in  4000.  Where  4000  ounces  of  matter  originally  existed,  only  3999  now 
remain;  the  missing  ounce  has  gone  off  in  the  form  of  radiation. 

This  makes  it  clear  that  we  must  not  expect  the  weights  of  the  various 
atoms  to  be  exact  multiples  of  the  weight  of  the  hydrogen  atom;  any 
such  expectation  would  ignore  the  weight  of  the  bottled-up  electro-mag- 
netic energy  which  is  capable  of  being  set  free  and  going  off  into  space  in 
the  form  of  radiation  as  the  atom  changes  its  make-up.  The  weight  of  this 
energy  is  relatively  small,  so  that  the  weights  of  the  atoms  must  be  ex- 
pected to  be  approximately,  although  not  exactly,  integral  multiples  of 
that  of  the  hydrogen  atom,  and  this  expectation  is  confirmed.  The  exact 
weight  of  our  atomic  building  is  not  simply  the  total  weight  of  all  its 
bricks;  something  must  be  added  for  the  weight  of  the  mortar— the  electro- 
magnetic energy — which  keeps  the  bricks  bound  together. 

Thus  the  normal  atom  consists  of  its  material  constituents — protons, 
electrons,  neutrons  and  positrons,  or  some  at  least  of  these — and  also  of 
energy,  which  also  contributes  something  to  its  weight.  When  the  atom 
re-arranges  itself,  either  spontaneously  or  under  bombardment,  protons 
and  electrons,  or  other  fragments  of  its  material  structure,  may  be  shot  off 
in  the  form  of  a-  and  (3-particles,  and  energy  may  also  be  set  free  in  the 
form  of  radiation.  This  radiation  may  either  take  the  form  of  y-rays,  or 
of  other  forms  of  visible  and  invisible  radiation.  The  final  weight  of  the 
atom  will  be  obtained  by  deducting  from  its  original  weight  not  only 
the  weight  of  all  the  ejected  electrons  and  protons,  but  also  the  weight 
of  all  the  energy  which  has  been  set  free  as  radiation. 


The  series  of  concepts  which  we  now  approach  are  difficult  to  grasp 
and  still  more  difficult  to  explain,  largely,  no  doubt,  because  our  minds 
receive  no  assistance  from  our  everyday  experience  of  nature.  It  becomes 
necessary  to  speak  mainly  in  terms  of  analogies,  parables  and  models  which 
can  make  no  claim  to  represent  ultimate  reality;  indeed,  it  is  rash  to 
hazard  a  guess  even  as  to  the  direction  in  which  ultimate  reality  lies. 

The  laws  of  electricity  which  were  in  vogue  up  to  about  the  end  of  the 
nineteenth  century— the  famous  laws  of  Maxwell  and  Faraday— required 


that  the  energy  of  an  atom  should  continually  decrease,  through  the  atom 
scattering  energy  abroad  in  the  form  of  radiation,  and  so  having  less  and 
less  left  for  itself.  These  same  laws  predicted  that  all  energy  set  free  in 
space  should  rapidly  transform  itself  into  radiation  of  almost  infinitesimal 
wave-length.  Yet  these  things  simply  did  not  happen,  making  it  obvious 
that  the  then  prevailing  electrodynamical  laws  had  to  be  given  up. 

CAVITY-RADIATION.  A  crucial  case  of  failure  was  provided  by  what  is 
known  as  "cavity-radiation."  A  body  with  a  cavity  in  its  interior  is  heated 
up  to  incandescence;  no  notice  is  taken  of  the  light  and  heat  emitted  by 
its  outer  surface,  but  the  light  imprisoned  in  the  internal  cavity  is  let  out 
through  a  small  window  and  analysed  into  its  constituent  colours  by  a 
spectroscope  or  diffraction  grating.  This  is  the  radiation  that  is  known 
as  "cavity-radiation."  It  represents  the  most  complete  form  of  radiation 
possible,  radiation  from  which  no  colour  is  missing,  and  in  which  every 
colour  figures  at  its  full  strength.  No  known  substance  ever  emits  quite 
such  complete  radiation  from  its  surface,  although  many  approximate  to 
doing  so.  We  speak  of  such  bodies  as  "full  radiators." 

The  nineteenth-century  laws  of  electromagnetism  predicted  that  the 
whole  of  the  radiation  emitted  by  a  full  radiator  or  from  a  cavity  ought 
to  be  found  at  or  beyond  the  extreme  violet  end  of  the  spectrum,  inde- 
pendently of  the  precise  temperature  to  which  the  body  had  been  heated. 
In  actual  fact  the  radiation  is  usually  found  piled  up  at  exactly  the  op- 
posite end  of  the  spectrum,  and  in  no  case  does  it  ever  conform  to  the 
predictions  of  the  nineteenth  century  laws,  or  even  begin  to  think  of 
doing  so. 

In  the  year  1900  Professor  Planck  of  Berlin  discovered  experimentally 
the  law  by  which  cavity-radiation  is  distributed  among  the  different 
colours  of  the  spectrum.  He  further  shewed  how  his  newly-discovered  law 
could  be  deduced  theoretically  from  a  system  of  electromagnetic  laws 
which  differed  very  sensationally  from  those  then  in  vogue. 

Planck  imagined  all  kinds  of  radiation  to  be  emitted  by  systems  of 
vibrators  which  emitted  light  when  excited,  much  as  tuning  forks  emit 
sound  when  they  are  struck.  The  old  electrodynamical  laws  predicted 
that  each  vibration  should  gradually  come  to  rest  and  then  stop,  as  the 
vibrations  of  a  tuning  fork  do,  until  the  vibrator  was  in  some  way  excited 
again.  Rejecting  all  this,  Planck  supposed  that  a  vibrator  could  change 
its  energy  by  sudden  jerks,  and  in  no  other  way;  it  might  have  one,  two, 
three,  four  or  any  other  integral  number  of  units  of  energy,  but  no  inter- 
mediate fractional  numbers,  so  that  gradual  changes  of  energy  were 
rendered  impossible.  The  vibrator,  so  to  speak,  kept  no  small  change, 
and  could  only  pay  out  its  energy  a  shilling  at  a  time  until  it  had  none 


left.  Not  only  so,  but  it  refused  to  receive  small  change,  although  it  was 
prepared  to  accept  complete  shillings.  This  concept,  sensational,  revolu- 
tionary and  even  ridiculous,  as  many  thought  it  at  the  time,  was  found  to 
lead  exactly  to  the  distribution  of  colours  actually  observed  in  cavity-ra- 

In  1917  Einstein  put  the  concept  into  the  more  precise  form  which  now 
prevails.  According  to  a  theory  previously  advanced  by  Professor  Niels 
Bohr  of  Copenhagen,  an  atomic  or  molecular  structure  does  not  change 
its  configuration,  or  dissipate  away  its  energy,  by  gradual  stages;  on  the 
contrary,  the  changes  are  so  abrupt  that  it  is  almost  permissible  to  regard 
them  as  a  series  of  sudden  jumps  or  jerks.  Bohr  supposed  that  an  atomic 
structure  has  a  number  of  possible  states  or  configurations  which  are 
entirely  distinct  and  detached  one  from  another,  just  as  a  weight  placed 
on  a  staircase  has  only  a  possible  number  of  positions;  it  may  be  3  stairs 
up,  or  4  or  5,  but  cannot  be  3 %  or  3%  stairs  up.  The  change  from  one 
position  to  another  is  generally  effected  through  the  medium  of  radiation. 
The  system  can  be  pushed  upstairs  by  absorbing  energy  from  radiation 
which  falls  on  it,  or  may  move  downstairs  to  a  state  of  lower  energy  and 
emit  energy  in  the  form  of  radiation  in  so  doing.  Only  radiation  of  a 
certain  definite  colour,  and  so  of  a  certain  precise  wave-length,  is  of  any 
account  for  effecting  a  particular  change  of  state.  The  problem  of  shifting 
an  atomic  system  is  like  that  of  extracting  a  box  of  matches  from  a  penny- 
in-the-slot  machine;  it  can  only  be  done  by  a  special  implement,  to  wit  a 
penny,  which  must  be  of  precisely  the  right  size  and  weight — a  coin  which 
is  either  too  small  or  too  large,  too  light  or  too  heavy,  is  doomed  to  fail. 
If  we  pour  radiation  of  the  wrong  wave  length  on  to  an  atom,  we  may  re- 
produce the  comedy  of  the  millionaire  whose  total  wealth  will  not  procure 
him  a  box  of  matches  because  he  has  not  a  loose  penny,  or  we  may  re* 
produce  the  tragedy  of  the  child  who  cannot  obtain  a  slab  of  chocolate 
because  its  hoarded  wealth  consists  of  farthings  and  half-pence,  but  we 
shall  not  disturb  the  atom.  When  mixed  radiation  is  poured  on  to  a  col- 
lection of  atoms,  these  absorb  the  radiation  of  just  those  wave-lengths 
which  are  needed  to  change  their  internal  states,  and  none  other;  radiation 
of  all  other  wave-lengths  passes  by  unaffected. 

This  selective  action  of  the  atom  on  radiation  is  put  in  evidence  in  a 
variety  of  ways;  it  is  perhaps  most  simply  shewn  in  the  spectra  of  the  sun 
and  stars.  Dark  lines  similar  to  those  which  Fraunhofer  observed  in  the 
solar  spectrum  are  observed  in  the  spectra  of  practically  all  stars  and  we 
can  now  understand  why  this  must  be.  Light  of  every  possible  wave-length 
streams  out  from  the  hot  interior  of  a  star,  and  bombards  the  atoms  which 
form  its  atmosphere.  Each  atom  drinks  up  that  radiation  which  is  of 


precisely  the  right  wave-length  for  it,  but  has  no  interaction  of  any  kind 
with  the  rest,  so  that  the  radiation  which  is  finally  emitted  from  the  star 
is  deficient  in  just  the  particular  wave-lengths  which  suit  the  atoms.  Thus 
the  star  shews  an  absorption  spectrum  of  fine  lines.  The  positions  of  these 
lines  in  the  spectrum  shew  what  types  of  radiation  the  stellar  atoms  have 
swallowed,  and  so  enable  us  to  identify  the  atoms  from  our  laboratory 
knowledge  of  the  tastes  of  different  kinds  of  atoms  for  radiation.  But 
what  ultimately  decides  which  types  of  radiation  an  atom  will  swallow, 
and  which  it  will  reject? 

It  had  been  part  of  Planck's  theory  that  radiation  of  each  wave-length 
has  associated  with  it  a  certain  amount  of  energy,  called  the  "quantum," 
which  depends  on  the  wave-length  and  on  nothing  else.  The  quantum 
is  supposed  to  be  proportional  to  the  "frequency,"  or  number  of  vibrations 
of  the  radiation  per  second,  and  so  is  inversely  proportional  to  the  wave- 
length of  the  radiation — the  shorter  the  wave-length,  the  greater  the 
energy  of  the  quantum,  and  conversely.  Red  light  has  feeble  quanta,  violet 
light  has  energetic  quanta,  and  so  on. 

Einstein  now  supposed  that  radiation  of  a  given  type  could  effect  an 
atomic  or  molecular  change,  only  if  the  energy  needed  for  the  change 
is  precisely  equal  to  that  of  a  single  quantum  of  the  radiation.  This  is 
commonly  known  as  Einstein's  law;  it  determines  the  precise  type  of 
radiation  needed  to  work  any  atomic  or  molecular  penny-in-the-slot 

We  notice  that  work  which  demands  one  powerful  quantum  cannot 
be  performed  by  two,  or  indeed  by  any  number  whatever,  of  feeble  quanta. 
A  small  amount  of  violet  (high-frequency)  light  can  accomplish  what  no 
amount  of  red  (low-frequency)  light  can  effect. 

The  law  prohibits  the  killing  of  two  birds  with  one  stone,  as  well  as 
the  killing  of  one  bird  with  two  stones;  the  whole  quantum  is  used  up  in 
effecting  the  change,  so  that  no  energy  from  this  particular  quantum  is 
left  over  to  contribute  to  any  further  change.  This  aspect  of  the  matter  is 
illustrated  by  Einstein's  photochemical  law:  "in  any  chemical  reaction 
which  is  produced  by  the  incidence  of  light,  the  number  of  molecules 
which  are  affected  is  equal  to  the  number  of  quanta  of  light  which  are 
absorbed."  Those  who  manage  penny-in-the-slot  machines  are  familiar 
with  a  similar  law:  "the  number  of  articles  sold  is  exactly  equal  to  the 
number  of  coins  in  the  machine." 

If  we  think  of  energy  in  terms  of  its  capacity  for  doing  damage,  we  see 
that  radiation  of  short  wave-length  can  work  more  destruction  in  atomic 
structures  than  radiation  of  long  wave-length—a  circumstance  with 
which  every  photographer  is  painfully  familiar;  we  can  admit  as  much 


red  light  as  we  please  without  any  damage  being  done,  but  even  the 
tiniest  gleam  of  violet  light  spoils  our  plates.  Radiation  of  sufficiently 
short  wave-length  may  not  only  rearrange  molecules  or  atoms;  it  may 
break  up  any  atom  oa  which  it  happens  to  fall,  by  shooting  out  one  of 
its  electrons,  giving  rise  to  what  is  known  as  photoelectric  action.  Again 
there  is  a  definite  limit  of  frequency,  such  that  light  whose  frequency 
is  below  this  limit  does  not  produce  any  effect  at  all,  no  matter  how  in- 
tense it  may  be;  whereas  as  soon  as  we  pass  to  frequencies  above  this 
limit,  light  of  even  the  feeblest  intensity  starts  photoelectric  action  at 
once.  Again  the  absorption  of  one  quantum  breaks  up  only  one  atom, 
and  further  ejects  only  one  electron  from  the  atom.  If  the  radiation  has 
a  frequency  above  this  limit,  so  that  its  quantum  has  more  energy  than 
the  minimum  necessary  to  remove  a  single  electron  from  the  atom,  the 
whole  quantum  is  still  absorbed,  the  excess  energy  now  being  used  in 
endowing  the  ejected  electron  with  motion. 

ELECTRON  ORBITS.  These  concepts  are  based  upon  Bohr's  supposition 
that  only  a  limited  number  of  orbits  are  open  to  the  electrons  in  an  atom, 
all  others  being  prohibited  for  reasons  which  Bohr's  theory  did  not  fully 
explain,  and  that  an  electron  is  free  to  move  from  one  permitted  orbit 
to  another  under  the  stimulus  of  radiation.  Bohr  himself  investigated  the 
way  in  which  the  various  permitted  orbits  are  arranged.  Modern  investi- 
gations indicate  the  need  for  a  good  deal  of  revision  of  his  simple  concepts, 
but  we  shall  discuss  these  in  some  detail,  partly  because  Bohr's  picture  of 
the  atom  still  provides  the  best  working  mechanical  model  we  have,  and 
partly  because  an  understanding  of  his  simple  theory  is  absolutely  es- 
sential to  the  understanding  of  the  far  more  intricate  theories  which  are 
beginning  to  replace  it. 

The  hydrogen  atom,  as  we  have  already  seen,  consists  of  a  single  proton 
as  central  nucleus,  with  a  single  electron  revolving  around  it.  The  nucleus, 
with  about  1847  times  the  weight  of  the  electron,  stands  practically  at 
rest  unagitated  by  the  motion  of  the  latter,  just  as  the  sun  remains  practi- 
cally undisturbed  by  the  motion  of  the  earth  round  it.  The  nucleus  and 
electron  carry  charges  of  positive  and  negative  electricity,  and  therefore 
attract  one  another;  this  is  why  the  electron  describes  an  orbit  instead  of 
flying  of?  in  a  straight  line,  again  like  the  earth  and  sun.  Furthermore, 
the  attraction  between  electric  charges  of  opposite  sign,  positive  and 
negative,  follows,  as  it  happens,  precisely  the  same  law  as  gravitation, 
the  attraction  falling  off  as  the  inverse  square  of  the  distance  between  the 
two  charges.  Thus  the  nucleus-electron  system  is  similar  in  all  respects 
to  a  sun-planet  system,  and  the  orbits  which  an  electron  can  describe 
around  a  central  nucleus  are  precisely  identical  with  those  which  a  planet 


can  describe  about  a  central  sun;  they  consist  of  a  system  of  ellipses  each 
having  the  nucleus  in  one  focus. 

Yet  the  general  concepts  of  quantum-dynamics  prohibit  the  electron 
from  moving  in  all  these  orbits  indiscriminately.  Bohr's  original  theory 
supposed  that  the  electron  in  the  hydrogen  atom  could  move  only  in 
certain  circular  orbits  whose  diameters  were  proportional  to  the  squares 
of  the  natural  numbers,  and  so  to  i,  4,  9,  16,  25,  ....  Bohr  subsequently 
modified  this  very  simple  hypothesis,  and  the  theory  of  wave-mechanics 
has  recently  modified  it  much  further. 

Yet  it  still  remains  true  that  the  hydrogen  atom  has  always  very  approxi- 
mately the  same  energy  as  it  would  have  if  the  electron  were  describing 
one  or  another  of  these  simple  orbits  of  Bohr.  Thus,  when  its  energy 
changes,  it  changes  as  though  the  electron  jumped  over  from  one  to  another 
of  these  orbits.  For  this  reason  it  is  easy  to  calculate  what  changes  of 
energy  a  hydrogen  atom  can  experience — they  are  precisely  those  which 
correspond  to  the  passage  from  one  Bohr  orbit  to  another.  For  example, 
the  two  orbits  of  smallest  diameters  in  the  hydrogen  atom  differ  in  energy 
by  i6Xio~12  erg.  If  we  pour  radiation  of  the  appropriate  wave-length  on 
to  an  atom  in  which  the  electron  is  describing  the  smallest  orbit  of  all,  it 
crosses  over  to  the  next  orbit,  absorbing  i6Xio"12  erg  of  energy  in  the 
process,  and  so  becoming  temporarily  a  reservoir  of  energy  holding  16 
X  io"12  erg.  If  the  atom  is  in  any  way  disturbed  from  outside,  it  may  of 
course  discharge  the  energy  at  any  time,  or  it  may  absorb  still  more 
energy  and  so  increase  its  store. 

If  we  know  all  the  orbits  which  are  possible  for  an  atom  of  any  type,  it 
is  easy  to  calculate  the  changes  of  energy  involved  in  the  various  transi- 
tions between  them.  As  each  transition  absorbs  or  releases  exactly  one 
quantum  of  energy,  we  can  immediately  deduce  the  frequencies  of  the 
light  emitted  or  absorbed  in  these  transitions.  In  brief,  given  the  arrange- 
ment of  atomic  orbits,  we  can  calculate  the  spectrum  of  the  atom.  In 
practice  the  problem  of  course  takes  the  converse  form:  given  the  spec- 
trum, to  find  the  structure  of  the  atom  which  emits  it.  Bohr's  model  of 
the  hydrogen  atom  is  a  good  model  at  least  to  this  extent — that  the  spec- 
trum it  would  emit  reproduces  the  hydrogen  spectrum  almost  exactly. 
Yet  the  agreement  is  not  quite  perfect,  and  for  this  reason  it  is  now 
generally  accepted  that  Bohr's  scheme  of  orbits  is  inadequate  to  account 
for  actual  spectra.  We  continue  to  discuss  Bohr's  scheme,  not  because  the 
atom  is  actually  built  that  way,  but  because  it  provides  a  working  model 
which  is  good  enough  for  our  present  purpose. 

An  essential,  although  at  first  sight  somewhat  unexpected,  feature  of 
the  whole  theory  is  that  even  if  the  hydrogen  atom  charged  with  its 


16  X  io"12  erg  of  energy  is  left  entirely  undisturbed,  the  electron  must, 
after  a  certain  time,  lapse  back  spontaneously  to  its  original  smaller  orbit, 
ejecting  its  16  X  io"12  erg  of  energy  in  the  form  of  radiation  in  so  doing. 
Einstein  shewed  that,  if  this  were  not  so,  then  Planck's  well-established 
"cavity-radiation"  law  could  not  be  true.  Thus,  a  collection  of  hydrogen 
atoms  in  which  the  electrons  describe  orbits  larger  than  the  smallest  pos- 
sible orbit  is  similar  to  a  collection  of  uranium  or  other  radio-active  atoms, 
in  that  the  atoms  spontaneously  fall  back  to  their  states  of  lower  energy 
as  the  result  merely  of  the  passage  of  time. 

The  electron  orbits  in  more  complicated  atoms  have  much  the  same 
general  arrangement  as  in  the  hydrogen  atom,  but  are  different  in  size. 
In  the  hydrogen  atom  the  electron  normally  falls,  after  sufficient  time,  to 
the  orbit  of  lowest  energy  and  stays  there.  It  might  be  thought  by  analogy 
that  in  more  complicated  atoms  in  which  several  electrons  are  describing 
orbits,  all  the  electrons  would  in  time  fall  into  the  orbit  of  lowest  energy 
and  stay  there.  Such  does  not  prove  to  be  the  case.  There  is  never  room 
for  more  than  one  electron  in  the  same  orbit.  This  is  a  special  aspect  of 
a  general  principle  which  appears  to  dominate  the  whole  of  physics.  It 
has  a  name — "the  exclusion-principle" — but  this  is  about  all  as  yet;  we  have 
hardly  begun  to  understand  it.  In  another  of  its  special  aspects  it  becomes 
identical  with  the  old  familiar  cornerstone  of  science  which  asserts  that 
two  different  pieces  of  matter  cannot  occupy  the  same  space  at  the  same 
time.  Without  understanding  the  underlying  principle,  we  can  accept 
the  fact  that  two  electrons  not  only  cannot  occupy  the  same  space,  but 
cannot  even  occupy  the  same  orbit.  It  is  as  though  in  some  way  the  electron 
spread  itself  out  so  as  to  occupy  the  whole  of  its  orbit,  thus  leaving 
room  for  no  other.  No  doubt  this  must  not  be  accepted  as  a  literal 
picture  of  things,  and  yet  the  modern  theory  of  wave-mechanics  sug- 
gests that  in  some  sense  (which  we  cannot  yet  specify  with  much  pre- 
cision) the  orbits  of  lowest  energy  in  the  hydrogen  atom  are  possible  orbits 
just  because  the  electron  can  completely  fill  them,  and  that  adjacent  orbits 
are  impossible  because  the  electron  would  fill  them  t  or  ii  times  over, 
and  similarly  for  more  complicated  atoms.  In  this  connection  it  is  per- 
haps significant  that  no  single  known  phenomenon  of  physics  makes  it 
possible  to  say  that  at  a  given  instant  an  electron  is  at  such  or  such  a 
point  in  an  orbit  of  lowest  energy;  such  a  statement  appears  to  be  quite 
meaningless  and  the  condition  of  an  atom  is  apparently  specified  with 
all  possible  precision  by  saying  that  at  a  given  instant  an  electron  is  in 
such  an  orbit,  as  it  would  be,  for  instance,  if  the  electron  had  spread 
itself  out  into  a  ring.  We  cannot  say  the  same  of  other  orbits.  As  we  pass 
to  orbits  of  higher  energy,  and  so  of  greater  diameter,  the  indeterminate- 


ness  gradually  assumes  a  different  form,  and  finally  becomes  of  but  little 
importance.  Whatever  form  the  electron  may  assume  while  it  is  describ- 
ing a  little  orbit  near  the  nucleus,  by  the  time  it  is  describing  a  very 
big  orbit  far  out  it  has  become  a  plain  material  particle  charged  with 

Thus,  whatever  the  reason  may  be,  electrons  which  are  describing  orbits 
in  the  same  atom  must  all  be  in  different  orbits.  The  electrons  in  their 
orbits  are  like  men  on  a  ladder;  just  as  no  two  men  can  stand  on  the 
same  rung,  so  no  two  electrons  can  ever  follow  one  another  round  in  the 
same  orbit.  The  neon  atom,  for  instance,  with  10  electrons  is  in  its  normal 
state  of  lowest  energy  when  its  10  electrons  each  occupy  one  of  the  10 
orbits  whose  energy  is  lowest.  For  reasons  which  the  quantum  theory  has 
at  last  succeeded  in  elucidating,  there  are,  in  every  atom,  two  orbits  in 
which  the  energy  is  equal  and  lower  than  in  any  other  orbit.  After  this 
come  eight  orbits  of  equal  but  substantially  higher  energy,  then  18  orbits 
of  equal  but  still  higher  energy,  and  so  on.  As  the  electrons  in  each 
of  these  various  groups  of  orbits  all  have  equal  energy,  they  are  commonly 
spoken  of,  in  a  graphic  but  misleading  phraseology,  as  rings  of  electrons. 
They  are  designated  the  K-ring,  the  L-ring,  the  M-ring  and  so  on. 
The  ,K-ring,  which  is  nearest  to  the  nucleus,  has  room  for  two  electrons 
only.  Any  further  electrons  are  pushed  out  into  the  L-ring,  which  has  room 
for  eight  electrons,  all  describing  orbits  which  are  different  but  of  equal 
energy.  If  still  more  electrons  remain  to  be  accommodated,  they  must 
go  into  the  M-ring  and  so  on. 

In  its  normal  state,  the  hydrogen  atom  has  one  electron  in  its  K~ring, 
while  the  helium  has  two,  the  L,  M,  and  higher  rings  being  unoccupied. 
The  atom  of  next  higher  complexity,  the  lithium  atom,  has  three  electrons, 
and  as  only  two  can  be  accommodated  in  its  X-ring,  one  has  to  wander 
round  in  the  outer  spaces  of  the  L-ring.  In  beryllium  with  four  electrons, 
two  are  driven  out  into  the  L-ring.  And  so  it  goes  on,  until  we  reach 
neon  with  10  electrons,  by  which  time  the  L-ring  as  well  as  the  inner  X- 
ring  is  full  up.  In  the  next  atom,  sodium,  one  of  the  n  electrons  is 
driven  out  into  the  still  more  remote  M-ring,  and  so  on.  Provided  the 
electrons  are  not  being  excited  by  radiation  or  other  stimulus,  each  atom 
sinks  in  time  to  a  state  in  which  its  electrons  are  occupying  its  orbits  of 
lowest  energy,  one  in  each. 

So  far  as  our  experience  goes,  an  atom,  as  soon  as  it  reaches  this 
state,  becomes  a  true  perpetual  motion  machine,  the  electrons  continuing 
to  move  in  their  orbits  (at  any  rate  on  Bohr's  theory)  without  any  of 
the  energy  of  their  motion  being  dissipated  away,  either  in  the  form  of 
radiation  or  otherwise.  It  seems  astonishing  and  quire  incomprehensible 


that  an  atom  in  such  a  state  should  not  be  able  to  yield  up  its  energy 
still  further,  but,  so  far  as  our  experience  goes,  it  cannot.  And  this 
property,  little  though  we  understand  it,  is,  in  the  last  resort,  responsible 
for  keeping  the  universe  in  being.  If  no  restriction  of  this  kind  inter- 
vened, the  whole  material  energy  of  the  universe  would  disappear  in 
the  form  of  radiation  in  a  few  thousand-millionth  parts  of  a  second.  If  the 
normal  hydrogen  atom  were  capable  of  emitting  radiation  in  the  way 
demanded  by  the  nineteenth-century  laws  of  physics,  it  would,  as  a  direct 
consequence  of  this  emission  of  radiation,  begin  to  shrink  at  the  rate  of 
over  a  metre  a  second,  the  electron  continually  falling  to  orbits  of  lower 
and  lower  energy.  After  about  a  thousand-millionth  part  of  a  second  the 
nucleus  and  the  electron  would  run  into  one  another,  and  the  whole  atom 
would  probably  disappear  in  a  flash  of  radiation.  By  prohibiting  any 
emission  of  radiation  except  by  complete  quanta,  and  by  prohibiting  any 
emission  at  all  when  there  are  no  quanta  available  for  dissipation,  the 
quantum  theory  succeeds  in  keeping  the  universe  in  existence  as  a  going 

It  is  difficult  to  form  even  the  remotest  conception  of  the  realities  under- 
lying all  these  phenomena.  The  recent  branch  of  physics  known  as 
"wave  mechanics"  is  at  present  groping  after  an  understanding,  but  so 
far  progress  has  been  in  the  direction  of  co-ordinating  observed  phenomena 
rather  than  in  getting  down  to  realities.  Indeed,  it  may  be  doubted 
whether  we  shall  ever  properly  understand  the  realities  ultimately  in- 
volved; they  may  well  be  so  fundamental  as  to  be  beyond  the  grasp  of  the 
human  mind. 

It  is  just  for  this  reason  that  modern  theoretical  physics  is  so  difficult 
to  explain,  and  so  difficult  to  understand.  It  is  easy  to  explain  the  motion 
of  the  earth  round  the  sun  in  the  solar  system.  We  see  the  sun  in  the 
sky;  we  feel  the  earth  under  our  feet,  and  the  concept  of  motion  is 
familiar  to  us  from  everyday  experience.  How  different  when  we  try 
to  explain  the  analogous  motion  of  the  electron  round  the  proton  in 
the  hydrogen  atom!  Neither  you  nor  I  have  any  direct  experience  of 
either  electrons  or  protons,  and  no  one  has  so  far  any  inkling  of  what 
they  are  really  like.  So  we  agree  to  make  a  sort  of  model  in  which  the 
electron  and  proton  are  represented  by  the  simplest  things  known  to  us, 
tiny  hard  spheres.  The  model  works  well  for  a  time  and  then  suddenly 
breaks  in  our  hands.  In  the  new  light  of  the  wave  mechanics,  the  hard 
sphere  is  seen  to  be  hopelessly  inadequate  to  represent  the  electron.  A  hard 
sphere  has  always  a  definite  position  in  space;  the  electron  apparently 
has  not.  A  hard  sphere  takes  up  a  very  definite  amount  of  room,  an 
electron— well,  it  is  probably  as  meaningless  to  discuss  how  much  room  an 


electron  takes  up  as  it  is  to  discuss  how  much  room  a  fear,  an  anxiety  or 
an  uncertainty  takes  up,  but  if  we  are  pressed  to  say  how  much  room 
an  electron  takes  up,  perhaps  the  best  answer  is  that  it  takes  up  the  whole 
of  space.  A  hard  sphere  moves  from  one  point  to  the  next;  our  model 
electron,  jumping  from  orbit  to  orbit  in  Bohr's  model  hydrogen  atom, 
certainly  does  not  behave  like  any  hard  sphere  of  our  waking  experience, 
and  the  real  electron — if  there  is  any  such  thing  as  a  real  electron — 
probably  even  less.  Yet  as  our  minds  have  so  far  failed  to  conceive  any 
better  picture  of  the  atom  than  this  very  imperfect  model,  we  can  only 
proceed  by  describing  phenomena  in  terms  of  it. 

Edition  of  1934 

Touring  the  Atomic  World 


do  at  the  moment  why  not  go  on  a  trip  into  an  invisible  world  ?  No 
money  is  required,  no  packing,  or  long,  tiresome  rides.  Just  a  fertile  imag- 
ination. Pick  up  an  object,  any  object,  and  look  at  it.  Then  imagine  that 
you  are  slowly  shrinking  in  size.  Say  the  object  you  are  holding  is  a  white 
handkerchief.  As  you  shrink,  the  handkerchief  seems  to  expand  enor- 
mously. At  first  it  looks  as  big  as  a  circus  tent.  But  you're  still  becoming 
smaller.  Now  as  you  stand  on  the  handkerchief,  it  forms  a  great,  white 
plain  as  far  as  your  eye  can  see.  Still  you  grow  smaller,  and  you  become 
aware  that  great  cracks  are  opening  in  your  white  plain.  These  aren't  the 
result  of  an  earthquake,  nor  the  crevasses  in  a  glacier.  They  simply  prove 
that  no  matter  how  tightly  woven  your  handkerchief  may  seem  to  be  there 
are  spaces  between  the  threads.  As  you  grow  smaller  still,  the  spaces  seem 
to  widen  and  the  threads,  themselves,  become  larger.  You  can  sit  on  one 
now  and  hang  your  feet  over  the  side. 


The  thread  seems  to  be  a  very  safe  place.  Soon  you  can  wander  around 
on  top  of  it,  looking  over  the  side  and  enjoying  your  trip  to  the  utmost. 
But  there  are  still  surprises  to  come.  As  yet  you  aren't  even  within  sight 
of  the  invisible  world  you  have  started  out  to  visit.  Still,  you're  getting 
there.  For  now  the  ground — or  rather  the  thread — is  beginning  to  open  up 
beneath  your  feet.  You  see,  you're  still  diminishing  in  size.  In  comparison, 
the  thread  is  still  becoming  larger.  Now  you're  beginning  to  find  from 
first  hand  experience  that  threads  are  made  up  of  fibers.  And  there  are 
spaces  between  the  fibers,  just  as  there  are  between  the  threads.  So  you 
pick  your  way  carefully  along  first  one  fiber  and  then  another,  being  care- 
ful not  to  fall  into  the  canyons  between  them.  This  seems  easy  until  you 
find  that  the  fibers  themselves  are  beginning  to  show  gaps.  The  one  that 
at  first  was  just  a  platform  on  which  you  stood  is  now  assuming  giant 
proportions,  stretching  away  in  all  directions.  You  seem  to  be  getting  so 
small  that  you  can  just  sink  right  through  it.  And  that's  exactly  what  is 
happening,  for  you  slip  through  the  surface  of  the  fiber,  disappear  into  it. 
And  the  next  thing  you  know  you're  falling  through  space,  like  someone 
pitched  out  of  a  Buck  Rogers  spaceship. 

As  you  fall,  you  see  all  about  you  planets  and  suns  and  moons.  They  are 
arranged  into  tight  little  solar  systems.  And  then,  if  you  know  your  atomic 
physics,  you'll  realize  that  you  have  arrived  in  the  hitherto  invisible  world 
of  the  atoms.  You  are  falling  through  an  ultramicroscopic  universe,  peo- 
pled by  solar  systems  so  infinitesimal  that  billions  of  them  are  contained 
in  the  fiber  you  have  just  slipped  through.  Yet  there  is  still  room  for  your 
much  shrunken  body  to  pass  without  even  grazing  them.  Now  you  can 
pick  out  those  sections  of  the  atom  that  you  were  told  about  in  school. 
You  can  see  the  bodies  that  look  like  planets  and  moons  rotating  around  a 
central  sun.  You  know  that  those  are  the  electrons,  electrical  particles  hav- 
ing a  negative  electrical  charge.  Then  you  turn  your  attention  to  the  cen- 
tral sun,  itself.  You  know  that  this  is  the  nucleus  of  the  atom,  the  impor- 
tant central  mass  that  determines  the  character  of  the  entire  atomic  solar 
system.  It  is  made  up  of  a  number  of  different  particles,  known  variously 
as  protons,  mesotrons,  and  neutrons.  You  can  see  all  these  things.  But, 
unfortunately,  that  is  as  far  as  you  can  go.  You  cannot  explore  them 
freely  as  you  have  explored  the  handkerchief.  For  such  a  journey  you  need 
a  special  passport  available  to  only  a  few  men  on  earth.  Even  they  have 
not  yet  developed  the  last  passport  of  all,  the  one  that  will  allow  them  to 
solve  all  the  mysteries  of  the  nucleus  of  the  atom. 

The  man  who  has  come  closest  to  making  the  entire  trip  through  the 
invisible  atomic  world  is  Dr.  Ernest  O.  Lawrence,  developer  of  the  world 
famous  cyclotron  on  the  University  of  California  campus  and  winner  of 


that  most  coveted  award,  the  Nobel  Prize  in  Physics  for  1939.  Shake  off 
your  imaginative  spell,  come  back  to  your  normal  size,  and  let's  go  over 
the  story  of  Dr.  Lawrence's  trips  into  the  atomic  unknown.  After  your 
journey  you  have  the  proper  perspective  to  appreciate  the  difficulties  he 
and  his  colleagues  have  overcome  and  those  they  hope  to  overcome  in  the 
near  future.  You  know  now  from  your  own  experience  that  nothing  we 
can  see  in  this  world  of  ours  is  solid  no  matter  how  it  feels  to  the  touch. 
Everything  we  use,  everything  that  we  see,  feel,  touch,  or  taste  is  made 
in  the  final  analysis,  not  of  those  things  that  we  call  paper,  or  sugar,  or  salt, 
or  wood,  but  of  tiny  solar  systems,  called  atoms,  ultramicroscopic  worlds 
which  no  one  yet  has  ever  completely  explored,  but  which  hold  the  secret 
to  a  possible  re-making  of  our  world  in  the  forms  which  we  desire.  So, 
having  familiarized  yourself  with  the  invisible  world  through  your  imag- 
inative journey,  take  another  mind's  eye  tour  with  the  writer,  this  time 
to  the  University  of  California  campus  where  in  the  Radiation  Laboratory 
we  pick  up  the  story  of  one  of  science's  most  valuable  and  remarkable 
developments,  the  cyclotron. 

This  machine,  now  copied  in  all  parts  of  the  world,  was  first  set  in  oper- 
ation at  the  University  in  1929.  It  was  the  answer  to  a  physicist's  dream 
and  proof  of  the  old  saw  that  necessity  is  the  mother  of  invention.  Physi- 
cists had  been  interested  in  atoms  for  many  years.  They  knew  about  their 
arrangement  with  the  electrons  whirling  in  orbits  about  the  central 
nucleus.  They  also  knew  that  the  proportion  of  negative  and  positive 
charges  in  the  nucleus  and  the  number  of  these  charges  present  (in  other 
words,  the  pattern  and  size  of  the  nucleus)  determined  whether  the  atom 
was  one  of  hydrogen  gas,  carbon,  gold,  iron,  molybdenum,  or  some  other 
element.  However,  this  knowledge  was  not  enough.  What  the  physicists 
wanted  to  do  was  to  tear  the  atomic  world  apart  and  see  what  made  it  tick. 
This,  as  they  knew,  was  by  no  means  an  easy  task. 

The  atom  is  like  a  case-hardened  steel  safe  without  lock  or  combination. 
You  can  break  into  it  only  by  main  force  and  its  resistance  is  powerful. 
Around  itself  it  sets  up  a  field  of  force  which  presents  a  stout  barricade 
against  invasion.  The  nucleus  is  tightly  held  together  by  the  mutual  elec- 
trical attraction  of  the  particles  from  which  it  is  formed.  This  sets  up  a 
second  barrier.  And,  finally,  the  atom's  lack  of  size  works  to  the  disadvan- 
tage of  anyone  attempting  to  explore  its  mysteries.  After  your  imagina- 
tive journey  through  the  handkerchief,  you  probably  won't  be  surprised 
to  find  that  atoms  are  so  small  it  would  take  the  entire  population  of  the 
earth  ten  thousand  years  to  count  the  number  of  them  in  a  drop  of  water. 
Even  then  each  individual  counter  would  have  to  be  reduced  to  one-bil- 
lionth of  an  inch  in  height  in  order  to  see  an  atom.  At  that  he  would  be 


several  cuts  larger  than  you  were  when  you  fell  through  the  fiber  into  the 
atomic  universe.  So  you  see  the  atom's  lack  of  size  presents  a  real  prob- 
lem. The  use  of  any  ordinary  weapon  in  an  assault  on  the  nucleus  would 
be  like  using  a  sledge  hammer  to  break  into  a  grain  of  dust.  What  is 
required  is  some  force  small  enough  to  enter  the  atom  and  still  powerful 
enough  to  break  down  the  electrical  barricades  surrounding  it. 

Lord  Rutherford,  the  famous  English  physicist,  found  such  a  force  in 
the  natural  rays  emitted  by  radium.  These  are  called  "alpha  rays"  by  the 
scientists  and  are  composed  of  steady  streams  of  helium  atoms  thrown  out 
at  a  pace  of  approximately  10,000  miles  per  second.  They  are  caused  by  the 
disintegration  of  the  radium.  In  1919  Lord  Rutherford  used  these  rays  to 
perform  the  first  known  transmutation  of  elements;  or  the  act  of  changing 
one  element  into  another.  The  ancient  alchemists  tried  to  perform  trans- 
mutation by  heating  base  metals  with  what  they  called  "philosopher's 
stone"  to  produce  gold.  Much  to  their  dismay  gold  was  never  produced. 
Lord  Rutherford  went  about  his  transmutation  operations  in  quite  a  dif- 
ferent way.  He  sent  "alpha  rays"  crashing  into  the  nuclei  of  nitrogen  gas 
atoms  and,  after  the  shooting  was  over,  out  came  oxygen.  This  may  seem 
complicated  but  it  was  really  very  simple.  All  that  happened  was  that  the 
"alpha  rays"  crashing  into  the  nitrogen  atoms  knocked  a  few  particles  out 
of  their  nuclei.  The  nature  of  any  element  is  dependent  upon  the  size  and 
pattern  of  its  nucleus,  and  the  nuclei  of  the  nitrogen  atoms  were  so  rear- 
ranged that  a  new  element,  oxygen,  was  formed. 

The  success  of  Lord  Rutherford's  experiments  set  physicists  all  over  the 
world  at  bombarding  atoms  with  the  rays  of  radium.  Soon  they  found 
that  when  atomic  nuclei  were  rearranged  under  the  impact  of  a  flying 
particle,  tremendous  amounts  of  energy  were  released.  This  energy,  it 
appeared,  was  locked  up  inside  the  atom,  and,  when  a  few  particles  were 
split  off  the  nucleus,  some  of  the  power  leaked  out.  A  little  of  it  would  go 
a  long,  long  way.  For  the  sub-atomic  energy,  as  the  power  is  called,  locked 
up  in  the  nuclei  of  the  atoms  in  a  fraction  of  a  pint  of  water  would  drive 
a  battleship  from  New  York  to  Liverpool  and  back  again.  Physicists  were 
greatly  intrigued  by  the  knowledge  that  some  of  this  energy  could  be 
released  by  bombarding  and  partially  breaking  up  the  nuclei  of  atoms.  It 
revived  the  hope  that  some  day  atomic  energy  of  which  there  is  a  great 
and  unfailing  source  might  be  used,  instead  of  steam  or  electricity,  to  turn 
the  wheels  of  the  world's  factories. 

Yet  for  all  their  speculation  as  to  what  these  discoveries  might  mean 
the  physicists  still  knew  that  radium  was  not  the  ideal  atom-blaster  they 
sought.  They  were  really  in  the  same  position  as  the  medical  men  before 
the  invention  of  the  microscope,  and  the  astronomers  before  the  invention 


of  the  telescope.  These  two  inventions  revolutionized  medicine  and 
astronomy.  The  physicists  stood  on  the  threshold  of  discoveries  that  would 
revolutionize  our  knowledge  of  the  structure  of  the  world  and  everything 
that  lives  on  it.  They  needed  another  passport  into  the  unknown.  Radium 
had  provided  them  with  entry  into  the  problem.  But  radium  was  too 
expensive  for  one  thing  and  also  it  was  not  a  very  copious  source  of  "alpha 
rays."  A  search  began  for  some  other  method  of  smashing  atoms,  and  thus 
the  stage  was  set  for  Dr.  E.  O.  Lawrence  and  his  now-famous  cyclotron. 

Lawrence,  who  was  only  beginning  his  University  career  at  that  time, 
had  abandoned  the  idea  of  searching  for  some  'force  strong  enough  nat- 
urally to  break  into  the  atomic  citadel.  Instead  he  proposed  to  take  some 
weaker  force  and  step  it  up  by  degrees  until  finally  when  unleashed,  it 
could  overpower  the  atom's  defense.  Or  at  least  storm  a  -section  of  the 
barricade.  To  test  his  theory  he  built  the  first  cyclotron,  an  almost  pocket- 
sized  model.  It  worked,  as  did  a  series  of  other  slightly  larger  ones.  So  Dr. 
Lawrence  began  laying  his  plans  for  a  machine  that  could  really  generate 
some  power.  The  old  Federal  Telegraph  Company  had  been  forced  in 
1918  to  abandon  its  plans  for  constructing  a  wireless  station  in  China.  As 
a  result,  Federal  still  had  a  6o-ton  magnet  on*  its  hands.  Dr.  Leonard  F. 
Fuller,  then  vice-president  of  Federal  and  in  his'  first  year  as  -chairman  of 
the  department  of  electrical  engineering  at  the  University,  persuaded  the 
board  of  directors  to  give  the  magnet  to  Dr.  Lawrence.  Around  it  the 
young  physicist  built  an  85-ton  cyclotron,  the  first  really  efficient  atom- 
smasher  the  world  was  to  know. 

Of  course,  Dr.  Lawrence  and  his  co-workers  at  the  Radiation  Labora- 
tory had  no  inkling  that  they  were  about  to  turn  the  physical  world  topsy- 
turvy. They  just  hoped  the  monster  would  work  as  well  in  fact  as  it  did 
on  paper. 

On  paper  it  was  all  very  simple.  First,  a  circular  chamber  was  placed 
between  the  poles  of  the  magnet.  Then  all  air  was  removed  from  the 
chamber  and  heavy  hydrogen  gas  allowed  to-  flow  in.  This  so-called  heavy 
hydrogen  behaves  in  the  same  way  as  ordinary  hydrogen.  However,  while 
the  nuclei  of  ordinary  hydrogen  atoms  contain  one  positively  charged  par- 
ticle, or  proton,  heavy  hydrogen  nuclei  contain  two  such  particles  plus 
one  electron.  Consequently,  they  weigh  just  twice  as  much  as  the  nuclei 
of  ordinary  hydrogen  atoms.  They  are  known  as  deuterons. 

The  deuteron's  added  weight  makes  it  an  ideal  atomic  bullet.  And  here 
is  how  Dr.  Lawrence  planned  to  send  streams  of  deuterons  crashing  into 
the  nuclei  of  other  atoms  in  a  constant,  destructive  barrage:  Inside  the 
cyclotron  chamber  was  a  heated  filament  that  emitted  streams  of  elec- 
trons. These  particles  would  collide  with  the  electrons  surrounding  the 


nuclei  of  the  hydrogen  atoms  and  in  the  ensuing  mixup  the  nuclei  and 
their  satellites  would  become  separated.  The  deuterons  would  be  left  free 
to  float  around  the  chamber.  Eventually,  the  magnetic  force  set  up  by  the 
cyclotron's  magnet  would  pull  them  between  two  metal  grids  separated 
by  a  space  across  which  an  alternating  electrical  current  of  ten  or  fifteen 
thousand  volts  would  be  operating.  As  the  deuterons  floated  into  this 
space,  they  would  receive  a  heavy  shock,  and  under  this  stimulus  fly  off 
to'ward  the  side  of  the  chamber.  But  the  magnetic  field  would  pull  them 
back  again  in  a  semi-circular  path  until  they  again  came  between  the  two 
grids.  Again  they  would  be  shocked  and  be  sent  flying  out  toward  the 
side.  Ancl  again  the  magnet  would  pull  them  back  to  complete  one  full 
circle  of  the  chamber  and  be  shocked  again. 

At  each  jolt  from  the  current  the  deuterons  would  gather  more  energy. 
This  meant  that  they  would  go  flying  out  from  between  the  grids  with 
constantly  increasing  force  and  in  constantly  widening  circles.  So  you  get 
the  picture  of  the  atomic  bullets  receiving  shocks  one  right  after  thfe^other 
from  a  weak  electrical  force.  Each  time  the  bullets  receive  a  shock  their 
energy  is  increased  and  they  go  on,  describing  wider  and  wider  circles 
around  the  cyclotron  chamber.  Finally,  they  circle  so  widely  that  they 
reach  a  slit  in  the  chamber  wall  and  go  flying  out  into  the  open  air.  The 
whole  secret  of  the  thing  lies  in  making  sure  by  means  of  the  magnet  that 
the  atomic  bullets  are  forced  to  come  back  for  successive  shocks  until  their 
energy  is  built  up  to  the  point  where  they  can  force  their  way  to  the  exit. 
Dr.  Lawrence  figured  that  to  bombard  any  substance  with  his  atomic  bul- 
lets, all  he  had  to  do  was  clamp  this  substance  over  the  slit  and  let  the 
onrushing  stream  of  deuterons  crash  into  it.  This  then  was  the  theory  put 
to  the  crucial  test  in  1934  at  the  University  Radiation  Laboratory.  Dr. 
Lawrence  threw  the  switch  that  sent  a  high-powered  radio  transmitter 
pumping  energy  into  the  cyclotron  and  the  first  experiment  with  the  85- 
ton  machine  had  begun. 

If  he  and  his  colleagues  held  their  collective  breath  during  the  first  test, 
the  results  soon  showed  that  their  fear$  were  without  grounds.  Within  a 
short  time,  physicists  were  amazed  to  hear  that  Lawrence  and  his  cyclo- 
tron were  not  only  changing  familiar  elements  like  platinum,  into  other 
elements,  like  iridium  and  gold,  but  were  actually  producing  substances 
never  before  seen  on  earth.  These  were  the  artificially  radioactive  ele- 
ments. Perhaps  their  character  is  best  explained  by  illustration. 

One  of  the  experiments  performed  with  the  cyclotron  involved  the  bom- 
bardment of  iron  atoms  with  the  high-speed  deuterons  produced  by  the 
cyclotron.  When  the  deuterons  crashed  into  them  with  a  force  of  about 
eight  million  volts,  the  iron  atoms  were  broken  up.  Some  changed  into 


atoms  of  cobalt  or  manganese.  But  others  were  converted  into  a  new  form 
of  iron  which,  like  radium,  emitted  streams  of  electrically  charged  par- 
ticles. In  other  words,  this  new  iron  was  radioactive.  Thirty-four  different 
elements  were  subjected  to  bombardment  with  the  85-ton  cyclotron  and 
all  of  them  underwent  a  transformation,  many  turning  into  radioactive 
substances.  Among  the  artificial  radioactive  materials  produced  by  the 
cyclotron  were  sodium,  phosphorus,  iron,  and  iodine.  It  was  even  pos- 
sible by  bombarding  bismuth  to  produce  a  degenerate  form  of  radium, 
called  Radium  E. 

Another  interesting  product  of  these  atomic  bombardments  was  the 
neutron,  a  particle  often  found  in  the  atomic  nucleus.  It  adds  to  the  weight 
of  the  nucleus  but  has  no  electrical  charge,  hence  its  name.  When  atoms 
were  smashed  by  the  bullets  from  the  cyclotron,  they  flew  into  two  parts. 
One  might  be  an  atom  of  a  new  radioactive  element,  and  the  other  an 
atom  of  a  light  element  such  as  hydrogen  or  helium.  But  more  often  than 
either  of  these  two,  a  neutron  would  appear.  When  the  cyclotron  was 
going  full  blast,  ten  billion  of  these  particles  could  be  liberated  every 

While  neutrons  are  important  as  building-blocks  of  nature,  they  are 
also  worthy  of  notice  for  their  ability  to  destroy  matter.  A  fast  neutron 
rolling  along  at  the  speed  of  light  has  tremendous  penetrating  power. 
So  great  is  this  power,  in  fact,  that  even  though  the  225-ton  machine  is 
surrounded  by  lead  water  tanks  and  tin  cans  full  of  water  and  is  inside 
a  laboratory  with  thick  concrete  walls  neutrons  produced  by  its  atomic 
bombardments  have  been  detected  as  far  as  100  yards  from  the  building. 
When  the  neutrons  are  slowed  up  by  passage  through  a  sheet  of  paraffine, 
they  lose  part  of  their  penetrating  power,  at  the  same  time  gaining  tre- 
mendously in  their  ability  to  smash  anything  placed  in  their  path. 
Physicists  have  taken  advantage  of  this  phenomenon.  They  are  using 
slow  neutrons  for  many  experiments  in  which  a  high-powered  sub- 
atomic bullet  is  required. 

At  present  the  slow  neutron  is  the  bully  boy  being  groomed  for  the 
final  day  when  physicists  hope  to  break  into  the  treasure-house  of  atomic 

To  continue  his  research  on  the  fundamental  problem  of  atomic  struc- 
ture Dr.  Lawrence  plans  to  build  a  4900-ton  cyclotron,  approximately 
twenty-two  times  as  large  as  the  225-ton  machine  which  is  itself  the 
largest  atom-smasher  of  its  kind  in  the  world.  This  monster  would  cost 
from  a  million  to  a  million  and  a  half  dollars.  This  is  a  great  deal  of 
money  but  let's  see  what  it  would  buy.  .  .  . 


Dr.  Lawrence  points  out  that  even  the  tremendously  powerful  atomic 
bullets  thrown  out  by  the  225-ton  cyclotron  have  not  yet  forced  a  com- 
plete capitulation  of  the  atomic  citadel.  They  can  split  off  only  a  few  of 
the  particles  of  the  nucleus.  Before  physicists  can  solve  the  fundamental 
problem  of  the  forces  that  bind  together  the  atomic  nucleus  it  is  necessary 
that  this  tight  little  core  of  the  atom  be  completely  torn  apart.  An  atomic 
"explosion"  must  be  provoked. 

. . .  The  laboratory  in  which  these  tremendous  forces  will  be  unleashed 
for  atomic  study  will  be  placed  far  from  the  campus  proper.  We  have 
already  seen  how  the  225-ton  cyclotron  produces  rays  that  pass  through 
thick  lead  tanks  full  of  water,  through  the  concrete  sides  of  the  Radiation 
Laboratory,  and  out  for  more  than  100  yards  across  the  campus  of  the 
University.  These  forces  are  relatively  weak  in  comparison  with  those 
that  would  be  produced  by  a  4900-ton  machine.  Probably  no  practicable 
amount  of  artificial  sheathing  would  cut  down  the  radiation  reaching  the 
outside  sufficiently.  So  the  plans  now  are  to  place  the  machine  and  the 
laboratory  in  a  great  building  in  Strawberry  Canyon  in  the  Berkeley 
Hills.  Then  at  least  500  feet  will  separate  the  cyclotron  from  its  innocent 
neighbors.  To  protect  the  laboratory  staff  from  the  tremendous  amount 
of  radiation  that  will  be  produced,  the  machine  will  be  surrounded  by 
lead  water  jackets  15  feet  thick.  It  is  possible  also  that  the  control  room 
may  be  placed  underground  so  that  the  earth  will  provide  an  additional 
buffer  between  the  cyclotron  and  its  operators. 

In  the  higher  energy  ranges  within  reach  of  the  4900-ton  cyclotron 
and  with  the  much  more  powerful  atomic  bullets  produced  by  this  tre- 
mendous machine  entirely  new  forms  of  radiation  and  entirely  new  sub- 
stances will  be  produced  and  put  to  the  service  of  mankind.  Identity  of 
these  radiations  and  substances  can  only  be  guessed  at  but  certainly  they 
will  prove  of  the  greatest  importance  not  only  as  additions  to  our  funda- 
mental knowledge  of  the  behavior  of  atoms  but  also  as  contributions  to 
industry,  biology,  and  medicine.  It  may  be  possible  with  the  4900-ton 
cyclotron  to  transmute  any  element  into  another  at  will,  to  produce  any 
known  substance  and  many  new  ones  to  order.  This  would  give  us  com- 
plete mastery  of  all  the  physical  elements.  Still  it  wouldn't  touch  the  pos- 
sibilities of  the  achievement  Dr.  Lawrence  is  really  working  toward:  lib- 
eration of  the  power  contained  in  the  atomic  nucleus. 

Let's  review  again  the  facts  concerning  this  power.  The  nucleus  makes 
up  more  than  99  per  cent  of  the  mass  of  the  atom  and  contains  more  than 
99  per  cent  of  the  atom's  energy.  This  store  of  energy  has  never  been 
tapped  for  useful  purposes.  Nevertheless,  we  know  it  must  be  tremen- 
dous. Radium  releases  enough  energy  to  raise  its  own  weight  in  water  tc 


the  boiling  point  every  hour  and  it  continues  to  give  off  this  energy  for 
thousands  of  years.  Nor  is  radium  unique.  Locked  within  the  nuclei  of 
commoner  and  less  expensive  elements  are  like  funds  of  power.  At  the 
Radiation  Laboratory  Dr.  Malcolm  Henderson,  a  physicist  on  leave  from 
Princeton  University,  bombarded  13  grams  of  uranium.  He  found  that 
each  uranium  atom  he  was  able  to  split  gave  off  175,000,000  electron  volts 
of  energy.  From  those  results  he  calculated  that  eight  pounds  of  uranium 
contain  as  much  power  as  6,300  tons  of  fuel  oil,  and  that  a  little  over  a 
half-pound  of  uranium  would  warm  a  ton  of  water  to  3,860,000  degrees 
Centigrade,  or  convert  386,000  tons  of  ice  water  into  boiling  water.  If 
such  vast  amounts  of  energy  could  be  released  and  harnessed  for  practical 
purposes  we  would  never  again  have  to  worry  over  depletion  of  our  sup- 
plies of  coal  and  oil.  Conservation  of  natural  resources  would  become  but 
an  empty  phrase  that  once  was  popular  when  men  still  depended  upon 
minerals  for  power  and  heat. 

Now  how  to  release  this  energy?  You'll  remember  our  sub-atomic 
bruiser,  the  slow  neutron.  On  his  shoulders  rest  the  hopes  of  Dr.  Lawrence 
and  his  Radiation  Laboratory  staff.  Here  is  how  they  hope  to  put  him  to 
work.  First,  they  will  build  up  the  power  in  the  49Oo-ton  cyclotron  until  it 
is  producing  streams  of  deuterons  or  helium  atoms  carrying  energies  of 
more  than  100  million  volts.  These  charged  particles  will  be  sent  crashing 
into  some  element,  probably  uranium  at  first  because  it  has  been  used 
before  in  such  experiments.  Under  the  tremendous  impact  of  the  atomic 
bullets,  atoms  of  this  element  will  be  shattered.  Great  clouds  of  slow  neu- 
trons will  be  released.  With  their  power  to  destroy  they  will  blast  more 
atoms  of  the  element,  releasing  more  neutrons  to  impact  on  and  shatter 
more  atoms.  With  each  of  these  shattering  blows  energy  in  excess  of  175,- 
000,000  volts  will  be  released.  Thus  will  be  achieved  the  "chain  reaction," 
or  chain  of  atomic  explosions,  that  has  been  hoped  for  and  which  should 
be  attainable  with  the  4900-ton  cyclotron. 

When  I  went  to  see  Dr.  Lawrence,  I  was  a  bit  worried  about  what 
might  happen  when  this  chain  reaction  started.  After  all,  there  would  be 
an  almost  unbelievable  amount  of  energy  released.  What  if  they  couldn't 
stop  the  reaction  and  it  just  kept  going  on  releasing  more  and  more 
energy?  There  might  be  a  terrific  outburst  that  would  send  cyclotron, 
Nobel  prize  winner  and  everything  else  sailing  up  into  the  sky.  But  when 
I  broached  this  question,  Dr.  Lawrence  just  smiled  and  said,  "Well,  that's 
not  really  such  a  great  danger  because  the  neutron's  own  properties  will 
protect  us  from  such  an  eventuality.  You  see,  the  slow  neutron  has  great 
disintegrating  power.  We'll  use  this  power  to  release  the  sub-atomic 
energy.  But  as  the  explosions  continue,  the  element  we  are  breaking  up 
will  become  white  hot.  As  the  temperature  rises,  the  neutrons  will  streak 


along  at  a  constantly  faster  pace.  As  you  know,  a  neutron  loses  in  disinte- 
grating power  and  gains  in  penetrating  power  as  it  speeds  up.  Pretty  soon 
all  these  neutrons  released  will  be  just  passing  through  the  atoms  without 
destroying  them  and  the  reaction  will  come  to  a  natural  conclusion.  But 
by  that  time  we'll  already  have  obtained  enough  energy  to  last  us  a  good 
long  while." 


The  Discovery  of  Radium 


From  Madame  Curie 

baby  daughter  and  put  pans  on  the  fire,  in  a  wretched  laboratory 
at  the  School  of  Physics  a  woman  physicist  was  making  the  most  impor- 
tant discovery  of  modern  science. 

At  the  end  of  1897  the  balance  sheet  of  Marie's  activity  showed  two 
university  degrees,  a  fellowship  and  a  monograph  on  the  magnetization 
of  tempered  steel.  No  sooner  had  she  recovered  from  childbirth  than  she 
was  back  again  at  the  laboratory. 

The  next  stage  in  the  logical  development  of  her  career  was  the  doctor's 
degree.  Several  weeks  of  indecision  came  in  here.  She  had  to  choose  a 
subject  of  research  which  would  furnish  fertile  and  original  material.  Like 
a  writer  who  hesitates  and  asks  himself  questions  before  settling  the  sub- 
ject of  his  next  novel,  Marie,  reviewing  the  most  recent  work  in  physics 
with  Pierre,  was  in  search  of  a  subject  for  a  thesis. 

At  this  critical  moment  Pierre's  advice  had  an  importance  which  can- 
not be  neglected.  With  respect  to  her  husband,  the  young  woman  regarded 
herself  as  an  apprentice:  he  was  an  older  physicist,  much  more  experi- 
enced than  she.  He  was  even,  to  put  it  exactly,  her  chief,  her  "boss." 


But  without  a  doubt  Marie's  character,  her  intimate  nature,  had  a  great 
part  in  this  all-important  choice.  From  childhood  the  Polish  girl  had  car- 
ried the  curiosity  and  daring  of  an  explorer  within  her.  This  was  the  in- 
stinct that  had  driven  her  to  leave  Warsaw  for  Paris  and  the  Sorbonne, 
and  had  made  her  prefer  a  solitary  room  in  the  Latin  Quarter  to  the 
Dluskis'  downy  nest.  In  her  walks  in  the  woods  she  always  chose  the 
wild  trail  or  the  unfrequented  road. 

At  this  moment  she  was  like  a  traveler  musing  on  a  long  voyage.  Bent 
over  the  globe  and  pointing  out,  in  some  far  country,  a  strange  name  that 
excites  his  imagination,  the  traveler  suddenly  decides  to  go  there  and  no- 
where else:  so  Marie,  going  through  the  reports  of  the  latest  experimental 
studies,  was  attracted  by  the  publication  of  the  French  scientist  Henri  Bec- 
querel  of  the  preceding  year.  She  and  Pierre  already  knew  this  work;  she 
read  it  over  again  and  studied  it  with  her  usual  care. 

After  Roentgen's  discovery  of  X  rays,  Henri  Poincare  conceived  the 
idea  of  determining  whether  rays  like  the  X  ray  were  emitted  by  "flu- 
orescent" bodies  under  the  action  of  light.  Attracted  by  the  same  problem, 
Henri  Becquerel  examined  the  salts  of  a  "rare  metal,"  uranium.  Instead 
of  finding  the  phenomenon  he  had  expected,  he  observed  another,  alto- 
gether different  and  incomprehensible :  he  found  that  uranium  salts  spon- 
taneously emitted,  without  exposure  to  light,  some  rays  of  unknown  na 
ture.  A  compound  of  uranium,  placed  on  a  photographic  plate  surrounded 
by  black  paper,  made  an  impression  on  the  plate  through  the  paper.  And, 
like  the  X  ray,  these  astonishing  "uranic"  salts  discharged  an  electroscope 
by  rendering  the  surrounding  air  a  conductor. 

Henri  Becquerel  made  sure  that  these  surprising  properties  were  not 
caused  by  a  preliminary  exposure  to  the  sun  and  that  they  persisted  when 
the  uranium  compound  had  been  maintained  in  darkness  for  several 
months.  For  the  first  time,  a  physicist  had  observed  the  phenomenon  to 
which  Marie  Curie  was  later  to  give  the  name  of  radioactivity.  But  the 
nature  of  the  radiation  and  its  origin  remained  an  enigma. 

Becquerel's  discovery  fascinated  the  Curies.  They  asked  themselves 
whence  came  the  energy — tiny,  to  be  sure — which  uranium  compounds 
constantly  disengaged  in  the  form  of  radiation.  And  what  was  the  nature 
of  this  radiation?  Here  was  an  engrossing  subject  of  research,  a  doctor's 
thesis!  The  subject  tempted  Marie  most  because  it  was  a  virgin  field: 
Becquerel's  work  was  very  recent  and  so  far  as  she  knew  nobody  in  the 
laboratories  of  Europe  had  yet  attempted  to  make  a  fundamental  study 
of  uranium  rays.  As  a  point  of  departure,  and  as  the  only  bibliography, 
there  existed  some  communications  presented  by  Henri  Becquerel  at  the 


Academy  of  Science  during  the  year  1896.  It  was  a  leap  into  great  adven- 
ture, into  an  unknown  realm. 

There  remained  the  question  o£  where  she  was  to  make  her  experi- 
ments— and  here  the  difficulties  began.  Pierre  made  several  approaches  to 
the  director  of  the  School  of  Physics  with  practically  no  results:  Marie  was 
given  the  free  use  of  a  little  glassed-in  studio  on  the  ground  floor  of  the 
school.  It  was  a  kind  of  storeroom,  sweating  with  damp,  where  unused 
machines  and  lumber  were  put  away.  Its  technical  equipment  was  rudi- 
mentary and  its  comfort  nil. 

Deprived  of  an  adequate  electrical  installation  and  of  everything  that 
forms  material  for  the  beginning  of  scientific  research,  she  kept  her  pa- 
tience, sought  and  found  a  means  of  making  her  apparatus  work  in  this 

It  was  not  easy.  Instruments  of  precision  have  sneaking  enemies:  humid- 
ity, changes  of  temperature.  Incidentally  the  climate  of  this  little  work- 
room, fatal  to  the  sensitive  electrometer,  was  not  much  better  for  Marie's 
health.  But  this  had  no  importance.  When  she  was  cold,  the  young  woman 
took  her  revenge  by  noting  the  degrees  of  temperature  in  centigrade  in 
her  notebook.  On  February  6,  1898,  we  find,  among  the  formulas  and 
figures:  "Temperature  here  6° '25.  [About  44°  Fahrenheit.]  Six  de- 
grees .  .  .  !"  Marie,  to  show  her  disapproval,  added  ten  little  exclamation 

The  candidate  for  the  doctor's  degree  set  her  first  task  to  be  the  measure- 
ment of  the  "power  of  ionization"  of  uranium  rays — that  is  to  say,  their 
power  to  render  the  air  a  conductor  of  electricity  and  so  to  discharge  an 
electroscope.  The  excellent  method  she  used,  which  was  to  be  the  key  to 
the  success  of  her  experiments,  had  been  invented  for  the  study  of  other 
phenomena  by  two  physicists  well  known  to  her:  Pierre  and  Jacques 
Curie.  Her  technical  installation  consisted  of  an  "ionization  chamber,"  a 
Curie  electrometer  and  a  piezoelectric  quartz. 

At  the  end  of  several  weeks  the  first  result  appeared:  Marie  acquired 
the  certainty  that  the  intensity  of  this  surprising  radiation  was  propor- 
tional to  the  quantity  of  uranium  contained  in  the  samples  under  exam- 
ination, and  that  this  radiation,  which  could  be  measured  with  precision, 
was  not  affected  either  by  the  chemical  state  of  combination  of  the  ura- 
nium or  by  external  factors  such  as  lighting  or  temperature. 

These  observations  were  perhaps  not  very  sensational  to  the  uninitiated, 
but  they  were  of  passionate  interest  to  the  scientist.  It  often  happens  in 
physics  that  an  inexplicable  phenomenon  can  be  subjected,  after  some  in- 
vestigation, to  laws  already  known,  and  by  this  very  fact  loses  its  interest 
for  the  research  worker.  Thus,  in  a  badly  constructed  detective  story,  if  we 


are  told  in  the  third  chapter  that  the  woman  of  sinister  appearance  who 
might  have  committed  the  crime  is  in  reality  only  an  honest  little  house- 
wife who  leads  a  life  without  secrets,  we  feel  discouraged  and  cease  to 

Nothing  of  the  kind  happened  here.  The  more  Marie  penetrated  into 
intimacy  with  uranium  rays,  the  more  they  seemed  without  precedent, 
essentially  unknown.  They  were  like  nothing  else.  Nothing  affected  them. 
In  spite  of  their  very  feeble  power,  they  had  an  extraordinary  individuality. 

Turning  this  mystery  over  and  over  in  her  head,  and  pointing  toward 
the  truth,  Marie  felt  and  could  soon  affirm  that  the  incomprehensible 
radiation  was  an  atomic  property.  She  questioned:  Even  though  the  phe- 
nomenon had  only  been  observed  with  uranium,  nothing  proved  that 
uranium  was  the  only  chemical  element  capable  of  emitting  such  radia- 
tion. Why  should  not  other  bodies  possess  the  same  power?  Perhaps  it 
was  only  by  chance  that  this  radiation  had  been  observed  in  uranium  first, 
and  had  remained  attached  to  uranium  in  the  minds  of  physicists.  Now  it 
must  be  sought  for  elsewhere.  .  . . 

No  sooner  said  than  done.  Abandoning  the  study  of  uranium,  Marie 
undertook  to  examine  all  \nown  chemical  bodies,  either  in  the  pure  state 
or  in  compounds.  And  the  result  was  not  long  in  appearing:  compounds 
of  another  element,  thorium,  also  emitted  spontaneous  rays  like  those  of 
uranium  and  of  similar  intensity.  The  physicist  had  been  right:  the  sur- 
prising phenomenon  was  by  no  means  the  property  of  uranium  alone,  and 
it  became  necessary  to  give  it  a  distinct  name.  Mme  Curie  suggested  the 
name  of  radioactivity.  Chemical  substances  like  uranium  and  thorium, 
endowed  with  this  particular  "radiance,"  were  called  radio  elements. 

Radioactivity  so  fascinated  the  young  scientist  that  she  never  tired  of 
examining  the  most  diverse  forms  of  matter,  always  by  the  same  method. 
Curiosity,  a  marvelous  feminine  curiosity,  the  first  virtue  of  a  scientist, 
was  developed  in  Marie  to  the  highest  degree.  Instead  of  limiting  her  ob- 
servation to  simple  compounds,  salts  and  oxides,  she  had  the  desire  to 
assemble  samples  of  minerals  from  the  collection  at  the  School  of  Physics, 
and  of  making  them  undergo  almost  at  hazard,  for  her  own  amusement, 
a  kind  of  customs  inspection  which  is  an  electrometer  test.  Pierre  ap- 
proved, and  chose  with  her  the  veined  fragments,  hard  or  crumbly,  oddly 
shaped,  which  she  wanted  to  examine. 

Marie's  idea  was  simple — simple  as  the  stroke  of  genius.  At  the  cross- 
roads where  Marie  now  stood,  hundreds  of  research  workers  might  have 
remained,  nonplussed,  for  months  or  even  years.  After  examining  all 
known  chemical  substances,  and  discovering — as  Marie  had  done — the 
radiation  of  thorium,  they  would  have  continued  to  ask  themselves  in 


vain  whence  came  this  mysterious  radioactivity.  Marie,  too,  questioned 
and  wondered.  But  her  surprise  was  translated  into  fruitful  acts.  She  had 
used  up  all  evident  possibilities.  Now  she  turned  toward  the  unplumbed 
and  the  unknown. 

She  knew  in  advance  what  she  would  learn  from  an  examination  of 
the  minerals,  or  rather  she  thought  she  knew.  The  specimens  which  con- 
tained neither  uranium  nor  thorium  would  be  revealed  as  totally  "inac- 
tive." The  others,  containing  uranium  or  thorium,  would  be  radioactive. 

Experiment  confirmed  this  prevision.  Rejecting  the  inactive  minerals, 
Marie  applied  herself  to  the  others  and  measured  their  radioactivity.  Then 
came  a  dramatic  revelation:  the  radioactivity  was  a  great  deal  stronger 
than  could  have  been  normally  foreseen  by  the  quantity  of  uranium  or 
thorium  contained  in  the  products  examined! 

"It  must  be  an  error  in  experiment,"  the  young  woman  thought;  for 
doubt  is  the  scientist's  first  response  to  an  unexpected  phenomenon. 

She  started  her  measurements  over  again,  unmoved,  using  the  same 
products.  She  started  over  again  ten  times,  twenty  times.  And  she  was 
forced  to  yield  to  the  evidence:  the  quantities  of  uranium  found  in  these 
minerals  were  by  no  means  sufficient  to  justify  the  exceptional  intensity 
of  the  radiation  she  observed. 

Where  did  this  excessive  and  abnormal  radiation  come  from?  Only 
one  explanation  was  possible:  the  minerals  must  contain,  in  small  quan- 
tity, a  much  more  powerfully  radioactive  substance  than  uranium  and 

But  what  substance?  In  her  preceding  experiments,  Marie  had  already 
examined  all  \nown  chemical  elements. 

The  scientist  replied  to  the  question  with  the  sure  logic  and  the  mag- 
nificent audaciousness  of  a  great  mind:  The  mineral  certainly  contained 
a  radioactive  substance,  which  was  at  the  same  time  a  chemical  element 
unknown  until  this  day:  a  new  element. 

A  new  element!  It  was  a  fascinating  and  alluring  hypothesis — but  still 
a  hypothesis.  For  the  moment  this  powerfully  radioactive  substance  existed 
only  in  the  imagination  of  Marie  and  of  Pierre.  But  it  did  exist  there.  It 
existed  strongly  enough  to  make  the  young  woman  go  to  see  Bronya  one 
day  and  tell  her  in  a  restrained,  ardent  voice: 

"You  know,  Bronya,  the  radiation  that  I  couldn't  explain  comes  from 
a  new  chemical  element.  The  element  is  there  and  I've  got  to  find  it.  We 
are  sure!  The  physicists  we  have  spoken  to  believe  we  have  made  an  error 
in  experiment  and  advise  us  to  be  careful.  But  I  am  convinced  that  I  am 
not  mistaken." 


These  were  unique  moments  in  her  unique  life.  The  layman  forms  a 
theatrical— and  wholly  false— idea  of  the  research  worker  and  of  his  dis- 
coveries. "The  moment  of  discovery"  does  not  always  exist:  the  scientist's 
work  is  too  tenuous,  too  divided,  for  the  certainty  of  success  to  crackle  out 
suddenly  in  the  midst  of  his  laborious  toil  like  a  stroke  of  lightning,  daz- 
zling him  by  its  fire.  Marie,  standing  in  front  of  her  apparatus,  perhaps 
never  experienced  the  sudden  intoxication  of  triumph.  This  intoxication 
was  spread  over  several  days  of  decisive  labor,  made  feverish  by  a  mag- 
nificent hope.  But  it  must  have  been  an  exultant  moment  when,  convinced 
by  the  rigorous  reasoning  of  her  brain  that  she  was  on  the  trail  of  new 
matter,  she  confided  the  secret  to  her  elder  sister,  her  ally  always.  .  .  . 
Without  exchanging  one  affectionate  word,  the  two  sisters  must  have  lived 
again,  in  a  dizzying  breath  of  memory,  their  years  of  waiting,  their  mutual 
sacrifices,  their  bleak  lives  as  students,  full  of  hope  and  faith. 

It  was  barely  four  years  before  that  Marie  had  written: 

Life  is  not  easy  for  any  of  us.  But  what  of  that?  We  must  have  persever- 
ance and  above  all  confidence  in  ourselves.  We  must  believe  that  we  are 
gifted  for  something,  and  that  this  thing,  at  whatever  cost,  must  be  attained. 

That  "something"  was  to  throw  science  upon  a  path  hitherto  unsus- 

In  a  first  communication  to  the  Academy,  presented  by  Prof.  Lipp- 
mann  and  published  in  the  Proceedings  on  April  12,  1898,  "Marie  Sklodov- 
ska  Curie"  announced  the  probable  presence  in  pitchblende  ores  of  a  new 
element  endowed  with  powerful  radioactivity.  This  was  the  first  stage  of 
the  discovery  of  radium. 

By  the  force  of  her  own  intuition  the  physicist  had  shown  to  herself 
that  the  wonderful  substance  must  exist.  She  decreed  its  existence.  But  its 
incognito  still  had  to  be  broken.  Now  she  would  have  to  verify  hypothesis 
by  experiment,  isolate  this  material  and  see  it.  She  must  be  able  to 
announce  with  certainty:  "It  is  there." 

Pierre  Curie  had  followed  the  rapid  progress  of  his  wife's  experiments 
with  passionate  interest.  Without  directly  taking  part  in  Marie's  work,  he 
had  frequently  helped  her  by  his  remarks  and  advice.  In  view  of  the 
stupefying  character  of  her  results,  he  did  not  hesitate  to  abandon  his  study 
of  crystals  for  the  time  being  in  order  to  join  his  efforts  to  hers  in  the  search 
for  the  new  substance. 

Thus,  when  the  immensity  of  a  pressing  task  suggested  and  exacted 
collaboration,  a  great  physicist  was  at  Marie's  side — a  physicist  who  was 
the  companion  of  her  life.  Three  years  earlier,  love  had  joined  this  excep- 


tional  man  and  woman  together — love,  and  perhaps  some  mysterious  fore- 
knowledge, some  sublime  instinct  for  the  work  in  common. 

The  valuable  force  was  now  doubled.  Two  brains,  four  hands,  now 
sought  the  unknown  element  in  the  damp  little  workroom  in  the  Rue 
Lhomond.  From  this  moment  onward  it  is  impossible  to  distinguish  each 
one's  part  in  the  work  of  the  Curies.  We  know  that  Marie,  having  chosen 
to  study  the  radiation  of  uranium  as  the  subject  of  her  thesis,  discovered 
that  other  substances  were  also  radioactive.  We  know  that  after  the  ex- 
amination of  minerals  she  was  able  to  announce  the  existence  of  a  new 
chemical  element,  powerfully  radioactive,  and  that  it  was  the  capital  im- 
portance of  this  result  which  decided  Pierre  Curie  to  interrupt  his  very 
different  research  in  order  to  try  to  isolate  this  element  with  his  wife.  At 
that  time — May  or  June,  1898 — a  collaboration  began  which  was  to  last 
for  eight  years,  until  it  was  destroyed  by  a  fatal  accident. 

We  cannot  and  must  not  attempt  to  find  out  what  should  be  credited  to 
Marie  and  what  to  Pierre  during  these  eight  years.  It  would  be  exactly 
what  the  husband  and  wife  did  not  want.  The  personal  genius  of  Pierre 
Curie  is  known  to  us  by  the  original  work  he  had  accomplished  before  this 
collaboration.  His  wife's  genius  appears  to  us  in  the  first  intuition  of  dis- 
covery, the  brilliant  start;  and  it  was  to  reappear  to  us  again,  solitary,  when 
Marie  Curie  the  widow  unflinchingly  carried  the  weight  of  a  new  science 
and  conducted  it,  through  research,  step  by  step,  to  its  harmonious  ex- 
pansion. We  therefore  have  formal  proof  that  in  the  fusion  of  their  two 
efforts,  in  this  superior  alliance  of  man  and  woman,  the  exchange  was 

Let  this  certainly  suffice  for  our  curiosity  and  admiration.  Let  us  not 
attempt  to  separate  these  creatures  full  of  love,  whose  handwriting  alter- 
nates and  combines  in  the  working  notebooks  covered  with  formulae, 
these  creatures  who  were  to  sign  nearly  all  their  scientific  publications  to- 
gether. They  were  to  write  "We  found"  and  "We  observed";  and  when 
they  were  constrained  by  fact  to  distinguish  between  their  parts,  they  were 
to  employ  this  moving  locution : 

Certain  minerals  containing  uranium  and  thorium  (pitchblende,  chal- 
colite, uranite)  are  very  active  from  the  point  of  view  of  the  emission  of 
Becquerel  rays.  In  a  preceding  communication,  one  of  us  showed  that  their 
activity  was  even  greater  than  that  of  uranium  and  thorium,  and  stated  the 
opinion  that  this  effect  was  due  to  some  other  very  active  substance  contained 
in  small  quantity  in  these  minerals. 

(Pierre  and  Marie  Curie:  Proceedings  of  the  Academy  of  Science,  July  18, 


Marie  and  Pierre  looked  for  this  "very  active"  substance  in  an  ore  of 
uranium  called  pitchblende,  which  in  the  crude  state  had  shown  itself  to 
be  four  times  more  radioactive  than  the  pure  oxide  of  uranium  that  could 
be  extracted  from  it.  But  the  composition  of  this  ore  had  been  known  for 
a  long  time  with  considerable  precision.  The  new  element  must  therefore 
be  present  in  very  small  quantity  or  it  would  not  have  escaped  the  notice 
of  scientists  and  their  chemical  analysis. 

According  to  their  calculations — "pessimistic"  calculations,  like  those 
of  true  physicists,  who  always  take  the  less  attractive  of  two  probabilities 
— the  collaborators  thought  the  ore  should  contain  the  new  element  to  a 
maximum  quantity  of  one  per  cent.  They  decided  that  this  was  very  little. 
They  would  have  been  in  consternation  if  they  had  known  that  the  radio- 
active element  they  were  hunting  down  did  not  count  for  more  than  a 
millionth  part  of  pitchblende  ore. 

They  began  their  prospecting  patiently,  using  a  method  of  chemical 
research  invented  by  themselves,  based  on  radioactivity;  they  separated  all 
the  elements  in  pitchblende  by  ordinary  chemical  analysis  and  then 
measured  the  radioactivity  of  each  of  the  bodies  thus  obtained.  By  suc- 
cessive eliminations  they  saw  the  "abnormal"  radioactivity  take  refuge  in 
certain  parts  of  the  ore.  As  they  went  on,  the  field  of  investigation  was 
narrowed.  It  was  exactly  the  technique  used  by  the  police  when  they 
search  the  houses  of  a  neighborhood,  one  by  one,  to  isolate  and  arrest  a 

But  there  was  more  than  one  malefactor  here:  the  radioactivity  was 
concentrated  principally  in  two  different  chemical  fractions  of  the  pitch- 
blende. For  M.  and  Mme  Curie  it  indicated  the  existence  of  two  new  ele- 
ments instead  of  one.  By  July  1898  they  were  able  to  announce  the  dis- 
covery of  one  of  these  substances  with  certainty. 

"You  will  have  to  name  it,"  Pierre  said  to  his  young  wife,  in  the  same 
tone  as  if  it  were  a  question  of  choosing  a  name  for  little  Irene. 

The  one-time  Mile  Sklodovska  reflected  in  silence  for  a  moment.  Then, 
her  heart  turning  toward  her  own  country  which  had  been  erased  from  the 
map  of  the  world,  she  wondered  vaguely  if  the  scientific  event  would  be 
published  in  Russia,  Germany  and  Austria — the  oppressor  countries — and 
answered  timidly : 

"Could  we  call  it  'polonium'?" 

In  the  Proceedings  of  the  Academy  for  July  1898  we  read: 

We  believe  the  substance  we  have  extracted  from  pitchblende  contains  a 
metal  not  yet  observed,  related  to  bismuth  by  its  analytical  properties.  If  the 
existence  of  this  new  metal  is  confirmed  we  propose  to  call  it  polonium, 
from  the  name  of  the  original  country  of  one  of  us. 


The  choice  of  this  name  proves  that  in  becoming  a  Frenchwoman  and 
a  physicist  Marie  had  not  disowned  her  former  enthusiasms.  Another 
thing  proves  it  for  us :  even  before  the  note  "On  a  New  Radioactive  Sub- 
stance Contained  in  Pitchblende"  had  appeared  in  the  Proceedings  of  the 
Academy,  Marie  had  sent  the  manuscript  to  her  native  country,  to  that 
Joseph  Boguski  who  directed  the  little  laboratory  at  the  Museum  of  In- 
dustry and  Agriculture  where  she  had  made  her  first  experiments.  The 
communication  was  published  in  Warsaw  in  a  monthly  photographic 
review  called  Swiatlo  almost  as  soon  as  in  Paris.  .  .  . 

We  find  another  note  worthy  of  remark. 

It  was  drawn  up  by  Marie  and  Pierre  Curie  and  a  collaborator  called 
G.  Bemont.  Intended  for  the  Academy  of  Science,  and  published  in  the 
Proceedings  of  the  session  of  December  26, 1898,  it  announced  the  existence 
of  a  second  new  chemical  element  in  pitchblende. 

Some  lines  of  this  communication  read  as  follows: 

The  various  reasons  we  have  just  enumerated  lead  us  to  believe  that  the 
new  radioactive  substance  contains  a  new  element  to  which  we  propose  to 
give  the  name  of  RADIUM. 

The  new  radioactive  substance  certainly  contains  a  very  strong  proportion 
of  barium;  in  spite  of  that  its  radioactivity  is  considerable.  The  radioactivity 
of  radium  therefore  must  be  enormous. 

The  Taming  of  Energy 


From  Atoms  in  Action 

June  day  or  a  day  in  December,  enough  energy  fell  on  the  earth 
during  that  twenty-four  hours  to  serve  humanity  for  several  centuries — 
enough  to  keep  the  world's  furnaces  roasting  and  its  refrigerators  icy,  to 
spin  its  wheels  and  refine  its  ores,  and  to  fill  for  several  hundred  years  every 
other  present  need  for  power.  The  wheels  of  civilization  are  kept  turning 
by  energy;  and  all  this  energy,  whether  we  draw  it  from  a  gallon  of  gaso- 
line, a  ton  of  coal,  or  a  pound  of  butter,  has  come  to  us  from  the  sun. 

So  long  as  the  sun  keeps  shining  we  appear  to  have  little  cause  to  worry 
about  running  out  of  energy,  and  the  best  evidence  indicates  that  our  pow- 
erhouse in  the  heavens  will  still  be  glowing  brilliantly  a  billion  years  from 
now.  Unfortunately,  however,  most  of  the  energy  we  are  now  using  came 
from  the  sun  in  ages  past,  and  we  are  drawing  heavily  on  the  earth's  sav- 
ings account  of  coal  and  oil  instead  of  using  our  current  energy  income. 
Even  though  the  sun  sends  us  two  hundred  thousand  times  as  much  power 
as  we  use,  most  of  this  slips  through  our  fingers,  because  we  have  not  yet 
learned  how  to  convert  sunlight  efficiently  into  those  forms  of  energy 
which  are  useful  for  civilized  living. 

Select  on  a  map  any  convenient  desert,  and  look  at  an  area  twenty  miles 
square — an  area  which  would  about  cover  the  sprawling  environs  of  a 
great  city.  Year  after  year  enough  sunlight  is  lavished  on  this  small  sandy 
waste  to  satisfy  perpetually  the  power  needs  of  the  entire  population  of  the 
United  States  at  the  present  rate  of  power  consumption.  In  fact,  grimy 
miners  digging  six  thousand  tons  of  coal  from  the  gloomy  depths  of  the 
earth  obtain  only  an  amount  of  energy  equivalent  to  that  swallowed  on  a 
sunny  day  by  a  single  square  mile  of  land  or  sea. 

Almost  every  material  problem  of  living  turns  out  in  the  last  analysis 
to  be  a  problem  of  the  control  of  energy.  The  householder,  when  he  has 



paid  his  bills  for  fuel  and  electricity,  is  likely  to  consider  that  he  has  taken 
care  of  his  energy  requirements  for  the  month,  yet  each  bill  from  the  gro- 
cer or  the  milliner  is  quite  as  truly  a  bill  for  energy.  We  do  not  buy  a  bas- 
ket of  strawberries  for  the  carbon,  oxygen,  and  nitrogen  atoms  they  con- 
tain, but  for  the  energy  stored  by  these  atoms  when  they  join  together  in 
molecules  to  form  sugars,  starches,  flavors,  and  vitamines.  That  part  of  the 
cost  of  a  lady's  hat  which  does  not  represent  business  acumen  on  the  part 
of  the  milliner  is  for  stored  and  directed  energy — the  atoms  of  matter  of 
which  the  hat  is  composed  are  permanent,  and  will  still  exist  when  the  hat 
has  been  discarded  and  burned.  Only  energy  and  knowledge  of  how  to 
apply  it  are  needed  to  re-create  a  hat  from  its  smoke  and  ashes! 

Even  such  materials  as  gold,  silver,  and  copper  represent  true  wealth 
only  as  they  represent  the  energy  required  to  find,  collect,  and  purify  these 
metals.  Our  supply  of  matter  on  earth  is  not  changing  appreciably,  for 
although  a  little  hydrogen  and  helium  leak  off  from  the  top  of  the  atmos- 
phere, far  more  matter  than  we  lose  in  this  way  is  brought  to  the  earth  by 
meteorites.  Iron  may  rust  or  be  scattered,  but  it  cannot  be  lost  so  long  as 
sufficient  energy  remains  to  reconcentrate  and  re-refine  it.  Many  a  mine 
long  abandoned  as  worthless  has  brought  in  a  fortune  when  cheaper  power 
or  a  more  efficient  concentrating  process  has  made  worth  while  the  recov- 
ery of  further  metal  from  its  scrap-heap.  Only  energy  is  needed  to  gather 
as  much  of  every  material  as  we  may  need  from  the  air,  the  land,  or  the 

Energy  is  wealth,  and  in  the  case  of  apprenticed  sunlight,  wealth  of  a 
particularly  desirable  kind,  for  it  is  freshly  created  and  does  not  involve 
robbing  the  poor,  taxing  the  rich,  or  despoiling  the  earth  of  materials  which 
may  be  needed  by  our  descendants  as  much  as  by  ourselves.  Yet  this  energy 
is  free — to  him  who  can  discover  how  to  capture  and  control  it. 

The  scientist  who  is  most  concerned  with  the  investigation  and  control 
of  energy  is  the  physicist.  In  his  researches  on  energy  the  physicist  works 
very  closely  with  the  chemist,  who  is  interested  primarily  in  matter.  Matter 
and  energy  are  always  closely  related;  and  physics  and  chemistry,  orig- 
inally a  single  science  called  natural  philosophy,  can  never  be  separated 
completely,  for  they  are  the  twin  sciences  which  deal  with  the  fundamental 
structure  of  our  physical  universe. 

The  chemist  gathers  the  minerals  and  fibers  and  oils  which  he  finds  in 
nature,  reduces  them  to  the  elementary  atoms  of  which  they  are  composed, 
and  then  causes  these  atoms  to  recombine  into  thousands  of  new  kinds  of 


molecules,  thus  forming  new  perfumes  and  dyes,  new  flavors  and  fabrics 
and  drugs. 

The  physicist,  however,  takes  apart  the  very  atoms  themselves,  sending 
through  wires  the  electrons  which  he  thus  collects,  and  operating  with 
them  his  telephones  and  X-ray  tubes  and  television  outfits.  Or  he  may 
induce  the  atoms  to  emit  light  rays  of  strange  new  colors,  rays  which  he 
bends  with  lenses  cleverly  designed  to  enable  him  to  discern  objects  which 
are  too  dark  or  small  or  transparent  otherwise  to  be  seen. 

As  the  physicist  has  gradually  learned  to  control  the  grosser  forms  of 
energy  such  as  heat  and  sound,  he  has  been  led  to  probe  deeper  and  deeper 
into  nature  in  studying  the  behavior  of  energy  in  its  finer  and  more  subtle 
forms,  such  as  light  and  electricity  and  magnetism.  He  has  now  succeeded 
in  penetrating  down  through  the  atom  into  its  tiny  nucleus  or  core,  and 
one  of  his  principal  interests  at  the  moment  (though  by  no  means  the  only 
one,  nor  necessarily  the  most  important  one)  is  to  take  sample  atom  cores 
apart  to  see  what  they  are  made  of  and  how  they  are  put  together.  The 
atom  is  being  taken  to  pieces  quite  literally,  for  when  one  of  the  modern 
"atom-smashing"  devices  is  put  into  operation  the  atomic  debris  comes 
flying  out  like  dirt  from  a  gopher  hole  in  which  a  very  industrious  puppy 
is  scratching. 

The  scientist  who  appears  preoccupied  with  the  center  of  the  atom  is 
burrowing  after  the  key  to  the  structure  of  matter  and  energy,  not  because 
he  expects  to  tap  the  energy  in  the  atom,  but  because  he  knows  that  before 
nature  can  be  controlled  she  must  be  understood.  The  physicist  who  is 
engaged  in  "pure"  or  fundamental  research  is  attempting  to  understand 
nature.  The  applied  physicist  is  attempting  to  control  nature.  The  two 
kinds  of  investigators  try  to  keep  in  close  collaboration,  but  physics  is  a  vast 
science  which  ranges  from  such  theoretical  subjects  as  Relativity  to  such 
practical  applications  as  the  phonograph,  as  the  interests  of  its  workers 
have  ranged  from  those  of  Einstein  to  those  of  Edison. 

.  .  .  "Atom  smashing"  (using  the  term  broadly  to  cover  fundamental 
research  into  the  structure  of  matter  and  energy)  pays  astonishing  divi- 
dends— not  a  mere  five  per  cent,  nor  one  hundred  per  cent,  but  hundiyds 
of  times  the  original  investment.  This  is  not  fanciful  romanticism,  but 
stark  bookkeeping  which  realistic  corporations,  headed  by  typical  American 
business  men,  have  many  times  demonstrated  to  their  stockholders. 

The  scientist,  like  the  artist,  creates  something  new  merely  by  rearrange- 
ment of  the  old.  An  industry  that  gets  its  profits  from  digging  coal  or 
pumping  oil  or  felling  timber  is  constantly  depleting  its  resources.  An 
industry  that  rests  on  a  physical  discovery  gets  its  profits  through  fresh 


Since  wealth  consists  ultimately  of  the  control  of  matter  and  energy,  the 
wealth  level  of  mankind  slowly  rises  as  science  learns  to  capture  a  con- 
stantly growing  fraction  of  the  energy  that  is  available  and  turn  it  more 
effectively  to  useful  ends.  A  factory  worker  in  the  United  States  is  paid 
several  times  as  much  in  real  wages  as  his  predecessor  received  a  generation 
ago.  While  management  may  justly  claim  credit  for  this  improvement,  it 
was  made  possible  only  by  utilizing  technological  achievements  resting  on 
scientific  discoveries,  which  made  the  labor  of  each  worker  more  produc- 
tive. For  the  wages  he  received  for  one  hour  of  labor  in  the  middle  1930*5 
a  factory  worker  in  Italy  could  buy  a  certain  amount  of  food,  a  similar 
worker  in  Great  Britain  could  buy  twice  as  much,  but  a  worker  in  the 
United  States  could  buy  four  times  as  much.  Economists  agree  that  tech- 
nological development  and  scientific  discovery  have  been  responsible  for 
this  higher  level  of  plenty  in  the  United  States.  Science  is  a  great  agency 
for  social  betterment,  for  the  victories  over  nature  which  result  from  its 
application  make  possible  increased  wages  and  profits  and  reduced  prices 
at  the  same  time. 

Experience  has  shown  no  better  way  of  eliminating  poverty  than  by  well- 
directed  "atom  smashing."  Poverty  can  best  be  abolished  by  replacing  it 
with  wealth;  and  the  systematic  investigation  of  matter  and  energy  without 
regard  to  immediate  practical  ends  has  turned  out  to  be  the  most  direct 
road  to  social  riches.  In  the  long  run  digging  for  truth  has  always  proved 
not  only  more  interesting,  but  more  profitable,  than  digging  for  gold.  If 
urged  on  by  the  love  of  digging,  one  digs  deeper  than  if  searching  for  some 
particular  nugget.  Practicality  is  inevitably  short-sighted,  and  is  self-handi- 
capped by  the  fact  that  it  is  looking  so  hard  for  some  single  objective  that 
it  may  miss  much  that  nature  presents  to  one  who  is  purposefully  digging 
for  whatever  may  turn  up. 

Each  dweller  in  the  United  States  is  now  served,  on  the  average,  by 
energy  equivalent  to  that  which  could  be  provided  by  thirty  slaves  such  as 
sweated  at  the  command  of  an  ancient  Egyptian  king.  In  making  this 
much  energy  available,  science  has  contributed  only  a  small  fraction  of 
what  it  can  contribute.  Human  beings  can  be  made  at  least  twenty  thou- 
sand times  as  wealthy  as  they  are  today;  but  only  the  fundamental  inves- 
tigation of  nature,  such  as  is  involved  in  "atom  smashing,"  will  show  how. 


Energy  can  neither  be  created  nor  destroyed  (except  as  it  can  be  changed 
into  matter  under  certain  extreme  conditions,  and  produced  from 
matter),  but  it  can  appear  in  any  of  a  dozen  or  more  forms.  If  the  physicist 
succeeds  in  backing  a  bit  of  energy  into  a  corner,  so  to  speak,  he  usually 


expects  il  to  disappear  like  a  witch  in  a  fairy  tale,  and  to  reappear  in  an 
entirely  different  form.  By  careful  study  of  many  typical  situations  he  has 
learned  where  to  lie  in  wait  for  the  reappearance  of  the  energy  so  that  he 
can  pounce  on  it  in  its  new  guise,  or,  if  it  stay  hidden,  ferret  out  its  place 
of  concealment.  All  of  our  most  useful  machines,  such  as  electric  motors 
and  kitchen  ranges  and  cameras,  are  merely  clever  devices  for  beguiling 
energy  of  one  form  into  changing  itself  into  another  form  which  we  desire 
to  use.  By  touching  a  match  to  a  gallon  of  gasoline  we  can  cause  the 
chemical  energy  which  the  gasoline  contains  to  be  transformed  into  thermal 
energy;  but  if  instead  we  use  a  spark  plug  in  an  automobile  cylinder,  much 
of  the  thermal  energy,  when  it  appears,  will  find  itself  harnessed  to  perform 
mechanical  work. 

The  most  useful  forms  of  energy  for  practical  purposes  are  those  we  call 
heat,  sound,  and  light,  and  the  mechanical,  electrical,  magnetic,  chemical, 
and  gravitational  forms.  When  we  have  learned  how  to  convert  energy 
from  any  one  of  these  forms  directly  into  any  other  at  will,  without  letting 
much  energy  escape  in  the  process,  the  millennium  will  have  arrived  so 
far  as  the  cost  of  living  is  concerned. 

If,  for  example,  we  knew  how  to  convert  electrical  energy  directly  into 
light,  the  problem  of  "cold  light"  would  be  solved.  At  present  we  must  use 
indirect  means,  as  in  the  incandescent  lamp,  where  electrical  energy  is 
forced  to  heat  a  tungsten  filament  and  thus  is  turned  into  heat  energy. 
When  heat  has  set  the  filament  glowing  some  of  its  energy  is  transformed 
into  useful  light  as  a  by-product,  but  nine-tenths  of  the  energy  is  wasted  as 
invisible  radiation,  boosting  our  electric  light  bills  to  ten  times  what  they 
should  be. 

An  example  of  the  many  useful  applications  which  often  result  from  the 
discovery  of  a  new  way  of  transforming  one  form  of  energy  into  another 
is  given  by  the  piezo-electric  crystal.  The  brothers  Pierre  and  Paul  Curie 
found  in  1880  that  sensitive  crystals  of  certain  types,  such  as  quartz  and 
Rochelle  salt,  shrink  and  swell  when  given  electric  shocks.  Thus  was  dis- 
covered a  new  method  of  changing  electrical  energy  into  mechanical 
energy.  The  crystals  were  found  also  to  generate  electric  charges  on  their 
surfaces  when  squeezed  or  stretched,  so  they  could  be  used  to  convert 
mechanical  energy  back  into  the  electrical  form  as  well.  The  Curie  brothers 
were  academic  physicists,  interested  chiefly  in  digging  out  facts  (Pierre, 
with  his  wife  Marie,  later  discovered  radium),  so  they  made  no  use  of  their 
discovery.  It  lay  unapplied  until  1917,  when,  during  the  World  War, 
another  physicist  decided  that  crystals  might  be  useful  for  detecting  the 
sound  waves  given  out  by  submarines.  His  work  was  so  successful  that  it 
suggested  further  fields  for  investigation,  and  later  we  shall  find  piezo- 


electric  crystals  being  used  for  such  diverse  purposes  as  keeping  radio 
broadcasting  stations  tuned  to  the  proper  frequency,  serving  as  micro- 
phones for  changing  sound  waves  into  electrical  waves,  and  forming 
wave-filters  which  keep  separate  more  than  two  hundred  telephone  conver- 
sations passing  simultaneously  over  the  same  pair  of  wires.  These  accom- 
plished crystals  also  make  excellent  phonograph  pickups,  can  be  used  as 
telephone  transmitters  and  receivers,  and  operate  the  most  accurate  clocks 
in  the  world,  which  tick  100,000  times  a  second.  Again,  by  tickling  such 
crystals  electrically  at  high  frequency  they  can  be  made  to  emit  super- 
sounds, which  are  of  value  for  cracking  crude  oil  to  increase  its  yield  of 
gasoline,  for  precipitating  smoke,  for  detecting  icebergs  or  other  obstruc- 
tions at  sea,  and  even  for  speeding  up  the  pickling  of  cucumbers  I 

The  delay  of  thirty-seven  years  in  putting  the  piezo-electric  crystal  to 
work  occurred  because  good  methods  of  applying  rapid  electric  shocks  to 
the  crystal  were  not  available  until  the  electronic  vacuum  tube  was  in- 
vented, which  in  turn  waited  on  the  discovery  of  the  electron.  Thus  the 
application  of  one  important  discovery  is  often  forced  to  await  the  birth 
of  another. 

Man's  physical  developments  involve  special  transformations  of  energy 
from  one  form  to  another — as  in  telephony,  where  sound  vibrations  are 
changed  into  electrical  vibrations,  carried  through  space  on  waves  or  over 
wires,  and  then  changed  back  into  sound  vibrations;  or  in  television,  where 
the  same  is  done  for  visual  images.  But  fundamental  to  all  such  processes 
is  the  transportation  and  storage  of  energy  in  bulk. 


Transporting  energy  from  place  to  place  keeps  millions  of  men  busy. 
Most  energy  is  transported  in  one  of  three  ways :  in  coal  carried  by  ships 
or  freight  cars;  in  oil  carried  by  ships,  tank  cars,  or  pumped  through  pipe 
lines;  or  sent  over  wires  as  electrical  power.  More  than  half  our  energy  is 
carried  in  coal.  Electrical  power  is  more  convenient  to  use  than  any  other 
kind,  but  even  when  energy  is  ultimately  to  be  delivered  in  electrical  form 
it  is  cheapest  at  present  to  carry  it  locked  in  coal  or  oil  for  as  much  of  its 
journey  as  possible. 

In  the  United  States  there  are  110,000  miles  of  pipes  through  which  black 
oil  flows,  sometimes  for  more  than  a  thousand  miles  on  a  single  journey; 
65,000  additional  miles  of  pipe  carry  natural  gas  for  fuel;  and  together 
these  buried  pipe  lines  form  a  transportation  system  almost  three-quarters 
as  long  as  all  the  railroad  tracks  of  the  country.  About  half  as  much  energy 
as  is  carried  by  oil  and  gas  flows  through  wires,  carried  by  electric  currents 


consisting  of  countless  electrons  sent  swinging  Irom  one  copper  atom  to 
the  next. 

To  carry  energy  to  its  user  costs  much  more  than  to  dig  it  out  of  the 
ground  as  coal  or  to  scoop  it  up  with  turbine  blades  from  a  waterfall. 
Though  a  ton  of  coal  costs  less  than  four  dollars  at  the  mine,  delivered  to 
the  ultimate  user  it  may  cost  four  times  as  much.  Electrical  energy  delivered 
in  the  home  now  costs  on  the  average  five  and  a  half  cents  a  kilowatt  hour, 
more  than  ten  times  its  cost  to  produce  in  wholesale  lots  at  a  steam  plant 
near  a  coal  mine.  There  is  great  need  for  development  of  cheaper  electrical 
methods  of  transmitting  power.  Standard  engineering  methods  are  begin- 
ning to  be  found  insufficient — new  methods  must  be  provided  by  applying 
physics  anew. 

At  present  electric  power  cannot  be  piped  economically  farther  than  a 
few  hundred  miles  unless  expensive  special  equipment  is  used;  only  when 
a  tremendous  load  of  power  can  be  sold  is  it  economical  to  provide  this 
equipment.  The  electrical  engineer  delivering  his  kilowatts  is  in  much  the 
situation  of  a  small  boy  carrying  home  sugar  from  the  grocery  store  in  a 
paper  sack  with  a  hole  in  its  bottom  which  lets  the  sugar  trickle  slowly 
away.  Since  the  engineer  cannot  now  afford  to  plug  the  hole,  only  those 
persons  can  afford  to  buy  electrical  sugar  whose  homes  are  within  a  few 
hundred  miles  of  an  electrical  power  store. 

It  has  long  been  known  that  the  most  efficient  way  to  send  power  over 
wires  of  a  given  size  is  to  keep  the  flow  of  electric  current  as  low  as  possible, 
and  make  the  voltage,  or  electrical  pressure  of  the  line,  as  great  as  possible, 
Engineers  have  a  working  rule  which  says  that  a  power  line  should  be 
operated  at  such  a  high  voltage  that  1000  volts-is  provided  for  each  mile  the 
power  is  carried.  Since  350,000  volts  is  about  the  economical  upper  limit 
of  voltage  practical  on  present  power  lines,  this  sets  a  350-mile  limit: 

In  1941  the  longest  power  line  stretched  270  miles  from  Boulder  Dam  to 
Los  Angeles.  To  carry  energy  from  such  great  water-power  developments 
as  Tennessee  Valley  to  the  large  cities  where  power  is  most  needed, 
methods  of  using  higher  voltages  must  "be  provided.  But  raising  the  voltage 
of  a  standard  power  line  above  350,000  volts  may  cause  the  bottom  to  drop 
out  of  the  electrical  sugar  bag — the  air,  the  line,  and  the  insulators  refuse  to 
co-operate  longer  in  keeping  the  electrical  flow  intact. 

Long-distance  transmission  lines  now  operate  with  alternating  current, 
briefly  written  A.C.  Electricity  is  first  pushed  into  one  wire  of*  the  line  and 
pulled  from  the  other,  and  then  the  push  and  pull  are  reversed.  Pushes 
and  pulls  are  usually  alternated  120  times  in  a  second,  giving  6o-cycle  A.C. 
Power  can  also  be  transmitted  with  direct  current  (D.-C.)  by  pumping 
electrons  continuously  into  one  wire*and  out  of  the  other,  and  it*  is  known 


that  with  such  D.C.  transmission  much  less  electricity  leaks  from  a  line 
than  with  A.C.  Short  lines  operating  at  more  than  a  million  volts  D.C. 
have  been  used  experimentally  to  carry  power.  However,  the  transformers 
which  give  the  most  convenient  means  of  stepping  electricity  up  from  a 
low  voltage  to  a  high  voltage,  or  stepping  it  down  again,  operate  only 
with  alternating  current.  For  safety,  power  must  be  generated  and  used 
at  low  voltages;  yet  for  economy  it  must  be  sent  over  a  long  line  at  high 
voltage.  This  combination  of  necessities  sets  a  pretty  dilemma. 

Here  the  electronic  vacuum  tube  enters  the  picture;  and  with  its  aid  the 
problem  may  well  be  solved.  With  tubes  of  one  type  direct  current  can  be 
changed  to  alternating  current  at  any  voltage.  By  using  tubes  of  a  second 
type  alternating  current  can  be  changed  to  direct.  Such  tubes  should  make 
it  possible  to  generate  alternating  current  power,  step  this  up  to  high 
voltage  with  transformers,  change  the  power  to  D.C.  with  a  vacuum  tube 
and  send  it  over  the  long-distance  power  line,  at  the  far  end  change  it  back 
to  A.C.  with  another  vacuum  tube,  and  then  step  it  down  with  a  trans- 
former to  the  desired  voltage  for  use.  This  process  of  sidestepping  nature's 
obstacles,  which  might  be  described  in  football  terms  as  a  double  lateral 
pass  with  a  forward  pass  between,  sounds  complex,  but  actually  it  is  simple 
once  the  vacuum  tubes  have  been  put  into  reliable  working  order..  A  trial 
installation  of  this  sort  has  been  kept  in  satisfactory  operation  by  the 
General  Electric  Company  in  Schenectady  for  several  years. 

An  entirely  different  attack  on  the  problem  of  high-voltage  D.C.  power 
transmission  has  been  suggested  by  the  work  of  an  atom-smashing 
physicist,  Dr.  Robert  J.  Van  de  Graaff,  and  his  collaborators.  They  were 
interested,  not  so  much  in  developing  a  new  means  of  transmitting  power, 
as  in  perfecting  a  high-voltage  machine  which  would  generate  5,000,000 
volts  with  which  to  hurl  electrical  bullets  against  the  cores  of  atoms  which 
were  to  be  smashed.  In  Van  de  Graaff's  generator,  electrons  are  sprayed 
against  wide  rubber  belts.  To  these  belts  the  electrons  stick,  and  by  them 
are  carried  up  into  a  large  metal  sphere,  which  they  gradually  charge  with 
electricity.  The  sphere  is  carefully  insulated  from  the  ground  by  a  sup- 
porting column  thirty  feet  high,  and  so  smooth  and  round  is  this  sphere 
that  electricity  can  leak  into  the  air  from  it  but  slowly.  If  electrons  are 
pumped  indefinitely  into  the  sphere  its  electrical  pressure  rises  until  finally 
a  voltage  is  reached  which  the  air  can  resist  no  longer,  and  a  great  flash  of 
artificial  lightning  jumps  between  the  sphere  and  any  near-by  object  con- 
nected to  the  ground.  With  -such  a  generator  several  million  volts  might 
be  applied  directly  to  a  power  line,  no  transformers  would  be  needed  at  the 
beginning  of  the  line,  and  extremely  weak  direct  currents  would  suffice 
to  transmit  large  amounts  of  power  with  little  loss. 


Scientists  have  envisaged  long  D.C.  lines  consisting  of  a  pipe,  buried  in 
the  earth  with  a  wire  stretched  down  its  center,  carrying  power  from  great 
hydraulic  turbo-generators,  or  from  steam  plants  located  near  coal  mines, 
to  any  city  in  the  country.  The  pipe  might  be  filled  with  carbon  tetra- 
chloride  vapor,  or  with  the  Freon  vapor  used  in  refrigerators,  to  reduce 
leakage  of  electricity  between  the  wire  and  the  pipe.  It  has  even  been  sug- 
gested that  the  pipe  might  be  evacuated  over  its  whole  length  of  more  than 
a  thousand  miles,  for  electricity  cannot  leak  across  a  well-evacuated  space. 
To  obtain  a  suitable  vacuum  thousands  of  high-speed  pumps  would  have 
to  be  kept  sucking  on  the  pipe  like  piglets  on  a  myriad-breasted  mother 
pig.  At  present  such  a  project  is  perhaps  visionary,  but  it  illustrates  how 
the  practicability  of  an  engineering  scheme  may  hinge  on  new  develop- 
ments of  physics — in  this  case,  on  a  high-voltage  generator  and  a  more 
efficient  vacuum  pump. 

Must  wires  always  be  used  to  carry  electric  power  from  place  to  place, 
or  could  rays  be  used  instead?  Dreamers  have  long  talked  of  powerful 
rays  which  could  be  focused  on  distant  machinery  to  which  energy  was 
thus  supplied.  Keeping  airplanes  aloft  without  fuel  is  a  favorite  applica- 
tion. At  present  no  rays  energetic  enough  for  this  purpose  and  at  the  same 
time  available  in  quantity  are  known  to  scientists.  Radio  waves  and  light 
waves  are  more  suited  to  such  comparatively  dainty  tasks  as  carrying 
messages  than  to  feeding  engines  with  power.  Machinery  can  be  operated 
with  the  energy  contained  in  rays  of  sunlight,  to  be  sure,  but  the  power 
these  carry  is  insufficiently  concentrated  to  be  worth  using  at  present,  even 
when  available.  Rays  of  more  concentrated  types  have  either  insufficient 
penetrating  power  to  travel  far  through  the  air,  or  are  uncontrollable,  or 
are  available  only  in  very  small  quantities.  Energy  can  be  most  readil) 
controlled  by  giving  it  matter  to  cling  to  when  it  is  to  be  stored,  concen- 
trated, or  carried  from  place  to  place  with  little  loss. 


To  store  energy  for  future  use  is  much  more  difficult  than  to  release 
energy  already  stored  in  matter.  When  fuel  is  burned,  the  chemical  energy 
stored  in  it  is  released  as  heat  energy;  but  the  reverse  process— unburning 
a  gallon  of  gasoline  or  a  cord  of  wood — is  very  slow  and  difficult.  Nature 
unburns  wood  when  she  uses  sunlight  in  plants  to  release  carbon  atoms 
from  the  carbon  dioxide  molecules  which  the  leaf  has  picked  up,  wafted 
through  the  air  from  some  long-forgotten  fire.  Man  has  not  yet  learned  to 
imitate  nature  in  this  regard,  though  he  is  beginning  to  get  some  clues  as 
to  how  the  job  is  done. 

One  can  store  energy  mechanically,  as  by  winding  a  clock  or  bending  a 


bow;  electrically,  as  by  charging  a  condenser;  gravitationally,  as  by  pump- 
ing water  into  a  high  reservoir;  thermally,  as  in  a  hot  water  bottle;  chem- 
ically, as  by  charging  a  storage  battery  or  growing  a  tree;  and  in  many 
other  ways.  All  involve  associating  energy  with  matter. 

In  comparing  storage  processes  a  most  important  question  is,  How  much 
energy  can  be  packed  into  each  pound  of  matter?  We  can  get  an  idea  of 
the  energy-holding  capacity  of  matter  by  seeing  how  much  energy  can  be 
released  from  a  pound  of  each  of  a  number  of  fuels;  this  energy  can  readily 
be  evaluated  in  terms  of  how  long  a  pound  of  the  fuel  would  keep  a 
6o-watt  incandescent  lamp  burning  if  all  its  energy  were  converted  into 
electric  power.  Thus,  a  pound  of  wood  would  keep  the  lamp  alight  for 
about  200  hours,  a  pound  of  coal  for  twice  as  long,  a  pound  of  gasoline 
for  900  hours.  Hydrogen  is  one  of  the  best  energy-storing  substances  obtain- 
able, for  in  a  pound  of  this  gas  is  stored  enough  energy  to  keep  the  lamp 
bright  for  nearly  2700  hours. 

Any  method  of  producing  such  fuels  is  a  method  of  storing  energy  in 
chemical  form;  and  chemical  storage,  in  which  the  energy  is  tucked 
between  atoms  when  these  are  grouped  together  to  form  molecules,  appears 
to  be  the  best  of  any  practical  method  now  available  to  store  energy  with 
little  weight.  Even  fuels  are  heavier  energy-storage  reservoirs  than  we 
would  like,  however;  witness  the  concern  of  the  aviator  whose  two  tons 
of  gasoline  must  carry  him  across  the  Atlantic  Ocean. 

Any  youth  who  wishes  to  win  fame  and  fortune  through  scientific 
discovery,  but  who  cannot  think  of  anything  which  needs  discovering, 
would  do  well  to  turn  his  attention  to  the  problem  of  storing  energy  lightly. 
If  he  could  invent  a  device  into  which  electrical  energy  could  be  fed,  which 
would  store  this  energy  chemically  and  later  release  it  again  as  electrical 
energy,  his  fortune  might  be  made — if  the  device  was  light  enough.  Such  a 
device  is,  of  course,  merely  a  storage  battery;  but  all  present  storage  bat- 
teries, though  extremely  efficient,  are  far  too  heavy  to  be  used  for  anything 
but  odd  jobs  such  as  starting  automobiles.  One  pound  of  ordinary  lead 
storage  battery,  when  fully  charged,  holds  less  than  one-twentieth  as  much 
energy  as  is  contained  in  a  pound  of  gasoline. 

If  a  storage  battery  weighing  less  than  one-tenth  as  much  as  present  bat- 
teries were  to  become  available,  the  electric  automobile  would  probably 
supersede  the  gasoline  motor  car  almost  immediately.  What  magic  does 
the  heavy  lead  atom,  now  used  for  almost  all  storage  of  electrical  energy, 
possess  which  enables  it  to  store  energy  and  give  this  out  again  at  the  will 
of  the  user,  which  is  not  possessed  by,  say,  the  lithium  or  the  beryllium 
atoms,  weighing  one-thirtieth  as  much  ?  There  seems  to  be  no  reason  for 
supposing  that  a  light  storage  battery  cannot  be  invented,  except  that  many 


people  have  tried  doing  this,  and  no  one  has  yet  succeeded.  Such  argu- 
ments have,  of  course,  never  deterred  resourceful  men.  To  invent  a  light 
battery,  the  old  method  was  to  start  by  trying  thousands  of  different  light 
materials;  the  new  method  is  carefully  to  study  nature  and  find  how  she 
packs  energy  into  atoms  and  molecules. 

Edition  of 

Space,  Time  and  Einstein* 


all  heard  of  the  Einstein  theory,  and  failure  to  understand  it  does 
not  seem  incompatible  with  the  holding  of  opinions  on  the  subject,  some- 
times of  a  militant  and  antagonistic  character. 

Twenty-four  years  have  elapsed  since  Einstein  published  his  first  paper 
on  relativity,  dealing  principally  with  certain  relations  between  mechanics 
and  optics.  Since  that  time  a  new  generation  has  grown  up  to  whom  pre- 
Einstein  science  is  a  matter  of  history,  not  of  experience.  Eleven  years 
after  his  first  paper  Einstein  published  a  second,  in  which  he  broadened 
and  extended  the  theory  laid  down  in  the  first  so  as  to  include  gravitation. 
And  now  again,  thirteen  years  later,  in  a  third  paper,  Einstein  has 
broadened  his  theory  still  farther  so  as  to  include  the  phenomena  of 
electricity  and  magnetism, 

In  view  of  the  rekindling  of  interest  in  Einstein  because  of  the  appear- 
ance of  his  latest  paper  it  may  be  worth  while  to  reexamine  and  restate 
the  primary  foundations  upon  which  his  theory  rests. 

The  general  interest  taken  in  this  subject  is  frequendy  a  matter  of 
wonder  to  those  of  us  who  must  give  it  attention  professionally,  for  there 

*  Publication  approved  by  the  Director  of  the  Bureau  of  Standards  of  the  U.  S.  Depart- 
ment of  Commerce. 


are  in  modern  physical  science  other  doctrines  which  run  closely  second 
to  that  of  Einstein  in  strangeness  and  novelty,  yet  none  o£  these  seems  to 
have  taken  any  particular  hold  on  popular  imagination. 

Perhaps  the  reason  for  this  is  that  these  theories  deal  with  ideas  which 
are  remote  from  ordinary  life,  while  Einstein  lays  iconoclastic  hands  on 
two  concepts  about  which  every  intelligent  person  believes  that  he  really 
knows  something — space  and  time. 

Space  and  time  have  been  regarded  "always,  everywhere  and  by  all," 
as  independent  concepts,  sharply  distinguishable  from  one  another,  with 
no  correlation  between  them.  Space  is  fixed,  though  we  may  move  about 
in  it  at  will,  forward  or  backward,  up  or  down;  and  wherever  we  go  our 
experience  is  that  the  properties  of  space  are  everywhere  the  same,  and 
are  unaltered  whether  we  are  moving  or  stationary.  Time,  on  the  other 
hand,  is  essentially  a  moving  proposition,  and  we  must  perforce  move 
with  it.  Except  in  memory,  we  can  not  go  back  in  time;  we  must  go 
forward,  and  at  the  rate  at  which  time  chooses  to  travel.  We  are  on  a 
moving  platform,  the  mechanism  of  which  is  beyond  our  control. 

There  is  a  difference  also  in  our  measures  of  space  and  time.  Space  may 
be  measured  in  feet,  square  feet  or  cubic  feet,  as  the  case  may  be,  but  time 
is  essentially  one-dimensional.  Square  hours  or  cubic  seconds  are  mean- 
ingless terms.  Moreover,  no  connection  has  ever  been  recognized  between 
space  and  time  measures.  How  many  feet  make  one  hour?  A  meaningless 
question,  you  say,  yet  something  that  sounds  very  much  like  it  has  (since 
Minkowski)  received  the  serious  attention  of  many  otherwise  reputable 
scientific  men.  And  now  comes  Einstein,  rudely  disturbing  these  old- 
established  concepts  and  asking  us  to  recast  our  ideas  of  space  and  time 
in  a  way  that  seems  to  us  fantastic  and  bizarre. 

What  has  Einstein  done  to  these  fundamental  concepts? 

He  has  introduced  a  correlation  or  connecting  link  between  what  have 
always  been  supposed  to  be  separate  and  distinct  ideas.  In  the  first  place, 
he  asserts  that  as  we  move  about,  the  geometrical  properties  of  space,  as 
evidenced  by  figures  drawn  in  it,  will  alter  by  an  amount  depending  on 
the  speed  of  the  observer's  motion,  thus  (through  the  concept  of  velocity) 
linking  space  with  time.  He  also  asserts  in  the  second  place  that  the  flow 
of  time,  always  regarded  as  invariable,  will  likewise  alter  with  the  motion 
of  the  observer,  again  linking  time  with  space. 

For  example,  suppose  that  we,  with  our  instruments  for  measuring 
space  and  time,  are  located  on  a  platform  which  we  believe  to  be  station- 
ary. We  can  not  be  altogether  certain  of  this,  for  there  is  no  other  visible 
object  in  the  universe  save  another  similar  platform  carrying  an  observer 
likewise  equipped :  but  when  we  observe  relative  motion  between  our  plat- 


form  and  the  other  it  pleases  our  intuition  to  suppose  our  platform  at 
rest  and  to  ascribe  all  the  motion  to  the  other. 

Einstein  asserts  that  if  this  relative  velocity  were  great  enough  we  might 
notice  some  strange  happenings  on  the  other  platform.  True,  a  rather 
high  velocity  would  be  necessary,  something  comparable  with  the  speed 
of  light,  say  100,000  miles  a  second;  and  it  is  tacitly  assumed  that  we 
would  be  able  to  get  a  glimpse  of  the  moving  system  as  it  flashed  by. 
Granting  this,  what  would  we  see? 

Einstein  asserts  that  if  there  were  a  circle  painted  on  the  moving  plat- 
form it  would  appear  to  us  as  an  ellipse  with  its  short  diameter  in  the 
direction  of  its  motion.  The  amount  of  this  shortening  would  depend 
upon  the  speed  with  which  the  system  is  moving,  being  quite  imper- 
ceptible at  ordinary  speeds.  In  the  limit,  as  the  speed  approached  that  of 
light,  the  circle  would  flatten  completely  into  a  straight  line — its  diameter 
perpendicular  to  the  direction  of  motion. 

Of  this  shortening,  says  Einstein,  the  moving  observer  will  be  uncon- 
scious, for  not  only  is  the  circle  flattened  in  the  direction  of  motion,  but 
the  platform  itself  and  all  it  carries  (including  the  observer)  share  in 
this  shortening.  Even  the  observer's  measuring  rod  is  not  exempt.  Laid 
along  that  diameter  of  the  circle  which  is  perpendicular  to  the  line  of 
motion  it  would  indicate,  say,  ten  centimeters;  placed  along  the  shortened 
diameter,  the  rod,  being  itself  now  shortened  in  the  same  ratio,  would 
apparently  indicate  the  same  length  as  before,  and  the  moving  observer 
would  have  no  suspicion  of  what  we  might  be  seeing.  In  fact,  he  might 
with  equal  right  suppose  himself  stationary  and  lay  all  the  motion  to  the 
account  of  our  platform.  And  if  we  had  a  circle  painted  on  our  floor  it 
would  appear  flattened  to  him,  though  not  to  us. 

Again,  the  clock  on  the  other  observer's  platform  would  exhibit  to  us, 
though  not  to  him,  an  equally  eccentric  behavior.  Suppose  that  other 
platform  stopped  opposite  us  long  enough  for  a  comparison  of  clocks,  and 
then,  backing  off  to  get  a  start,  flashed  by  us  at  a  high  speed.  As  it  passed 
we  would  see  that  the  other  clock  was  apparently  slow  as  compared  with 
ours,  but  of  this  the  moving  observer  would  be  unconscious. 

But  could  he  not  observe  our  clock  ? 

Certainly,  just  as  easily  as  we  could  see  his. 

And  would  he  not  see  that  our  clock  was  now  faster  than  his?  "No," 
says  Einstein.  "On  the  contrary,  he  would  take  it  to  be  slower." 

Here  is  a  paradox  indeed!  A's  clock  appears  slow  to  B  while  at  the 
same  time  B's  clock  appears  slow  to  A\  Which  is  right? 

To  this  question  Einstein  answers  indifferently: 

"Either.  It  all  depends  on  the  point  of  view." 


In  asserting  that  the  rate  of  a  moving  clock  is  altered  by  its  motion 
Einstein  has  not  in  mind  anything  so  materialistic  as  the  motion  inter- 
fering with  the  proper  functioning  of  the  pendulum  or  balance  wheel. 
It  is  something  deeper  and  more  abstruse  than  that.  He  means  that  the 
flow  of  time  itself  is  changed  by  the  motion  of  the  system,  and  that  the 
clock  is  but  fulfilling  its  natural  function  in  keeping  pace  with  the  altered 
rate  of  time. 

A  rather  imperfect  illustration  may  help  at  this  point.  If  I  were  traveling 
by  train  from  the  Atlantic  to  the  Pacific  Coast  it  would  be  necessary  for 
me  to  set  my  watch  back  an  hour  occasionally.  A  less  practical  but 
mathematically  more  elegant  plan  would  be  to  alter  the  rate  of  my  watch 
before  starting  so  that  it  would  indicate  the  correct  local  time  during  the 
whole  journey.  Of  course,  on  a  slow  train  less  alteration  would  be 
required.  The  point  is  this:  that  a  timepiece  keeping  local  time  on  the 
train  will  of  necessity  run  at  a  rate  depending  on  the  speed  of  the  train. 

Einstein  applies  a  somewhat  similar  concept  to  all  moving  systems, 
and  asserts  that  the  local  time  on  such  systems  runs  the  more  slowly  the 
more  rapidly  the  system  moves. 

It  is  no  wonder  that  assertions  so  revolutionary  should  encounter  general 
incredulity.  Skepticism  is  nature's  armor  against  foolishness.  But  there 
are  two  reactions  possible  to  assertions  such  as  these.  One  may  say:  "The 
man  is  crazy"  or  one  may  ask:  "What  is  the  evidence?" 

The  latter,  of  course,  is  the  correct  scientific  attitude.  To  such  a  question 
Einstein  might  answer  laconically:  "Desperate  diseases  require  desperate 

"But,"  we  reply,  "we  are  not  conscious  of  any  disease  so  desperate  as 
to  require  such  drastic  treatment." 

"If  you  are  not,"  says  Einstein,  "you  should  be.  Does  your  memory  run 
back  thirty  years?  Or  have  you  not  read,  at  least,  of  the  serious  contra- 
diction in  which  theoretical  physics  found  itself  involved  at  the  opening 
of  the  present  century?" 

Einstein's  reference  is  to  the  difficulty  which  arose  as  a  consequence  of 
the  negative  results  of  the  famous  Michelson-Morley  experiment  and 
other  experiments  of  a  similar  nature.  The  situation  that  then  arose  is 
perhaps  best  explained  by  an  analogy. 

If  we  were  in  a  boat,  stationary  in  still  water,  with  trains  of  water- 
waves  passing  us,  it  would  be  possible  to  determine  the  speed  of  the 
waves  by  timing  their  passage  over,  say,  the  length  of  the  boat.  If  the 
boat  were  then  set  in  motion  in  the  same  direction  in  which  the  waves 
were  traveling,  the  apparent  speed  of  the  waves  with  respect  to  the  boat 
would  be  decreased,  reaching  zero  when  the  boat  attained  the  speed  of 


the  waves;  and  if  the  boat  were  set  in  motion  in  the  opposite  direction 
the  apparent  speed  of  the  waves  would  be  increased. 

If  the  boat  were  moving  with  uniform  speed  in  a  circular  path,  the 
apparent  speed  of  the  waves  would  fluctuate  periodically,  and  from  the 
magnitude  of  this  fluctuation  it  would  be  possible  to  determine  the  speed 
of  the  boat. 

Now  the  earth  is  moving  around  the  sun  in  a  nearly  circular  orbit  with 
a  speed  of  about  eighteen  miles  per  second,  and  at  all  points  in  this  orbit 
light  waves  from  the  stars  are  constantly  streaming  by.  The  analogy  of 
the  boat  and  the  water-waves  suggested  to  several  physicists,  toward  the 
close  of  the  nineteenth  century,  the  possibility  of  verifying  the  earth's 
motion  by  experiments  on  the  speed  of  light. 

True,  the  speed  of  the  earth  in  its  orbit  is  only  one  ten-thousandth  of 
the  speed  of  light,  but  methods  were  available  of  more  than  sufficient 
precision  to  pick  up  an  effect  of  this  order  of  magnitude.  It  was,  there- 
fore, with  the  greatest  surprise,  not  to  say  consternation,  that  the  results 
of  all  such  experiments  were  found  to  be  negative;  that  analogy,  for 
some  unexplained  reason,  appeared  to  have  broken  down  somewhere 
between  mechanics  and  optics;  that  while  the  speed  of  water-waves  varied 
as  it  should  with  the  speed  of  the  observer,  the  velocity  of  light  seemed 
completely  unaffected  by  such  motion. 

Nor  could  any  fault  be  found  with  method  or  technique.  At  least  three 
independent  lines  of  experiment,  two  optical  and  one  electrical,  led  to  the 
same  negative  conclusion. 

This  breakdown  of  analogy  between  mechanics  and  optics  introduced 
a  sharp  line  of  division  into  physical  science.  Now  since  the  days  of 
Newton  the  general  trend  of  scientific  thought  has  been  in  the  direction 
of  removing  or  effacing  such  sharp  lines  indicating  differences  in  kind 
and  replacing  them  by  differences  in  degree.  In  other  words,  scientific 
thought  is  monistic,  seeking  one  ultimate  explanation  for  all  phenomena. 

Kepler,  by  his  study  of  the  planets,  had  discovered  the  three  well-known 
laws  which  their  motion  obeys.  To  him  these  laws  were  purely  empirical, 
separate  and  distinct  results  of  observation.  It  remained  for  Newton  to 
show  that  these  three  laws  were  mathematical  consequences  of  a  single 
broader  law — that  of  gravitation.  In  this,  Newton  was  a  monistic 

The  whole  of  the  scientific  development  of  the  nineteenth  century  was 
monistic.  Faraday  and  Oersted  showed  that  electricity  and  magnetism 
were  closely  allied.  Joule,  Mayer  and  others  pointed  out  the  equivalence 
of  heat  and  work.  Maxwell  correlated  light  with  electricity  and  mag- 
netism. By  the  close  of  the  century  physical  phenomena  of  all  kinds  were 


regarded  as  forming  one  vast,  interrelated  web,  governed  by  some  broad 
and  far-reaching  law  as  yet  unknown,  but  whose  discovery  was  confi- 
dently expected,  perhaps  in  the  near  future.  Gravitation  alone  obstinately 
resisted  all  attempts  to  coordinate  it  with  othtx  phenomena. 

The  consequent  reintroduction  of  a  sharp  line  between  mechanics  and 
optics  was  therefore  most  disturbing.  It  was  to  remove  this  difficulty 
that  Einstein  found  it  necessary  to  alter  our  fundamental  ideas  regarding 
space  and  time.  It  is  obvious  that  a  varying  velocity  can  be  made  to  appear 
constant  if  our  space  and  time  units  vary  also  in  a  proper  manner,  but 
in  introducing  such  changes  we  must  be  careful  not  to  cover  up  the 
changes  in  velocity  readily  observable  in  water-waves  or  sound  waves. 

The  determination  of  such  changes  in  length  and  time  units  is  a  purely 
mathematical  problem.  The  solution  found  by  Einstein  is  what  is  known 
as  the  Lorentz  transformation,  so  named  because  it  was  first  found  (in 
a  simpler  form)  by  Lorentz.  Einstein  arrived  at  a  more  general  formula 
and,  in  addition,  was  not  aware  of  Lorentz's  work  at  the  time  of  writing 
his  own  paper. 

The  evidence  submitted  so  far  for  Einstein's  theory  is  purely  retrospec- 
tive; the  theory  explains  known  facts  and  removes  difficulties.  But  it  must 
be  remembered  that  this  is  just  what  the  theory  was  built  to  do.  It  is  a 
different  matter  when  we  apply  it  to  facts  unknown  at  the  time  the 
theory  was  constructed,  and  the  supreme  test  is  the  ability  of  a  theory  to 
predict  such  new  phenomena. 

This  crucial  test  had  been  successfully  met  by  the  theory  of  relativity. 
In  1916  Einstein  broadened  his  theory  to  include  gravitation,  which  since 
the  days  of  Newton  had  successfully  resisted  all  attempts  to  bring  it  into 
line  with  other  phenomena.  From  this  extended  theory  Einstein  predicted 
two  previously  unsuspected  phenomena,  a  bending  of  light  rays  passing 
close  by  the  sun  and  a  shift  of  the  Fraunhofer  lines  in  the  solar  spectrum. 
Both  these  predictions  have  now  been  experimentally  verified. 

Mathematically,  Einstein's  solution  of  our  theoretical  difficulties  is 
perfect.  Even  the  paradox  of  the  two  clocks,  each  appearing  slower  than 
the  other,  becomes  a  logical  consequence  of  the  Lorentz  transformation. 
Einstein's  explanation  is  sufficient,  and  up  to  the  present  time  no  one  has 
been  able  to  show  that  it  is  not  necessary. 

Einstein  himself  is  under  no  delusion  on  this  point.  He  is  reported  to 
have  said,  "No  amount  of  experimentation  can  ever  prove  me  right;  a 
single  experiment  may  at  any  time  prove  me  wrong." 

Early  in  the  present  year  Einstein  again  broadened  his  theory  to  include 
the  phenomena  of  electricity  and  magnetism.  This  does  not  mean  that 
he  has  given  an  electromagnetic  explanation  of  gravitation;  many  attempts 


of  this  kind  have  been  made,  and  all  have  failed  in  the  same  respect — to 
recognize  that  there  is  no  screen  for  gravitation.  What  Einstein  has  done 
is  something  deeper  and  broader  than  that.  He  has  succeeded  in  finding 
a  formula  which  may  assume  two  special  forms  according  as  a  constant 
which  it  contains  is  or  is  not  zero.  In  the  latter  case  the  formula  gives 
us  Maxwell's  equations  for  an  electromagnetic  field;  in  the  former, 
Einstein's  equations  for  a  gravitative  field.  .  .  . 

Einstein's  aim  from  the  first  has  been  to  bring  order,  not  confusion; 
to  exhibit  all  the  laws  of  nature  as  special  cases  of  one  all-embracing 
law.  In  his  monism  he  is  unimpeachably  orthodox. 

But  there  are  other  monistic  philosophers  besides  scientific  men.  You 
will  recall  Tennyson's  vision  of 

One  law,  one  element, 

And  one  far-off,  divine  event 

To  which  the  whole  creation  moves. 


The  Foundations  of  Chemical  Industry 



by  throwing  one  brightly  colored  ball  after  the  other  into  the  air, 
catching  each  in  turn  and  throwing  it  up  again  until  he  has  quite  a 
number  moving  from  hand  to  hand.  The  system  which  he  keeps  in  motion 
has  an  orderly  structure.  He  changes  it  by  selecting  balls  of  different  colors, 
altering  the  course  or  the  sequence  of  the  balls,  or  by  adding  to  or 
diminishing  the  number  with  which  he  plays. 

With  this  figure  in  mind  let  us  use  our  imaginations.  Before  us  we  have 
an  assemblage  of  hundreds  of  thousands  of  jugglers  varying  in  their 
degree  of  accomplishment;  some  handle  only  one  ball,  others,  more 
proficient,  keep  several  in  motion,  and  there  are  still  others  of  an  as- 
tounding dexterity  who  play  with  an  hundred  or  more  at  once.  The  balls 
they  handle  are  of  ninety  different  colors  and  sizes.  The  jugglers  do  not 
keep  still  but  move  about  at  varying  rates;  those  handling  few  and  light 
balls  move  more  quickly  than  those  handling  many  or  heavier  ones. 
These  dancers  bump  into  each  other  and  when  they  do  so  in  certain 
cases  they  exchange  some  of  the  balls  which  they  are  handling  or  one 
juggler  may  take  all  of  those  handled  by  another,  but  in  no  case  are  the 
balls  allowed  to  drop. 


Now  imagine  the  moving  group  to  become  smaller  and  smaller  until 
the  jugglers  cease  to  be  visible  to  us,  even  when  they  dance  under  the 
highest  power  microscope.  If  someone  who  had  not  seen  them  were  to 
come  to  you  and  say  that  he  proposed  undertaking  the  problem  of  finding 
out  how  the  balls  were  moving  and  what  were  the  rules  of  the  exchanges 
made,  and  further  that  he  proposed  utilizing  his  knowledge  to  control 
what  each  minute  juggler  was  doing,  you  would  tell  him  that  his  task  was 



hopeless.  If  the  chemist  had  listened  to  such  advice  there  would  be 
no  chemical  industry  and  you  would  lose  so  much  that  you  would  not  be 
living  in  the  way  you  are. 

The  jugglers  are  the  electromagnetic  forces  of  matter,  the  balls  are  the 
atoms,  and  each  group  in  the  hands  of  the  juggler  is  a  molecule  of  a 
substance.  In  reality,  of  course,  instead  of  each  molecule  being  represented 
by  one  unit  we  should  multiply  our  jugglers  by  trillions  and  trillions. 


The  chemist,  without  even  seeing  them,  has  learned  to  handle  these 
least  units  of  materials  in  such  a  way  as  to  get  the  arrangements  which 
are  more  useful  from  those  less  useful.  This  power  he  has  acquired  as  the 
outcome  of  his  life  of  research,  his  desire  to  understand,  even  though 
understanding  brought  him  no  material  gain,  but  mere  knowledge. 
Because  of  his  patience  and  devotion  he  has  built  a  number  of  industries; 
all  have  this  in  common — they  serve  to  rearrange  atoms  of  molecules  or 
to  collect  molecules  of  one  kind  for  the  service  of  man. 


The  study  of  the  substances  of  the  earth's  crust,  of  the  air  over  and  of 
the  waters  under  earth,  which  has  led  us  to  our  present  knowledge  of  the 
electron,  atom,  and  molecule,  has  been  more  adventurous  than  many  a 
great  journey  made  when  the  world  was  young  and  the  frontier  of  the 
unknown  was  not  remote  from  the  city  walls.  Into  the  unknown  world 
of  things  upon  the  "sea  that  ends  not  till  the  world's  end"  the  man  of 
science  ventured,  and  he  came  back  laden  with  treasure  greater  than  all 
the  gold  and  precious  stones  ever  taken  from  the  earth.  He  gave  these  to 
others  and  he  fared  forth  again  without  waving  of  flags,  without  the 
benediction  of  holy  church,  with  no  more  than  the  courage  of  him  who 
would  win  Nature,  who  had  chosen  a  harder  road  than  that  of  the  great, 
made  famous  because  of  subduing  other  men.  He  took  no  arms  upon  his 
quest,  scarcely  enough  food  to  keep  body  and  soul  together,  but  instead, 
fire,  glass,  and  that  most  astounding  of  all  tools,  the  balance.  As  he  pushed 
farther  and  farther  on  his  great  venture  and  as  more  and  more  joined  his 
little  band,  he  brought  more  and  more  back  to  those  who  did  not  under- 
stand in  the  least  what  he  was  doing,  until  now  the  lives  of  all  men 
are  made  easier  if  not  happier  by  these  strange,  most  useful,  and 
most  potent  things  of  which  he  is  the  creator  by  reason  of  the  under- 
standing his  journeys  have  given  him — a  power  much  greater  than 
any  mere  black  magic. 


This  is  the  story  of  some  of  the  strange  treasure  found  by  him  in  the 
far  lands  that  are  about  us— treasure  found  by  learning  the  secret  of 
the  jugglers'  dance— the  dance  of  the  least  little  things  out  of  which  all 
we  know  is  fashioned. 


The  Great  Discovery 

In  Sicily  and  other  parts  of  the  earth  where  there  are  volcanoes,  lumps 
of  a  yellow  crumbly  "stone"  are  found,  called  brimstone  (a  corruption  of 
brcnnisteinn  or  burning  stone).  This  material  was  regarded  as  having 
curative  properties;  if  it  was  burned  in  a  house  the  bad  odors  of  the 
sickroom  of  primitive  times  were  suppressed.  Also  the  alchemists  found 
that  it  took  away  the  metallic  character  of  most  metals  and  they  con- 
sidered it  very  important  in  their  search  for  the  philosopher's  stone,  the 
talisman  that  was  to  turn  all  things  to  gold.  The  alchemists  found  also 
that  sulfur,  when  burned  over  water,  caused  the  water  to  become  acid,  and 
one  of  them  found  further  that  if  the  burning  took  place  in  the  presence 
of  saltpeter  the  acid  which  was  produced  was  much  stronger;  indeed,  if 
concentrated  it  was  highly  corrosive.  A  useless  find,  it  seemed,  of  interest 
only  to  the  alchemist  who  hoped  to  become  rich  beyond  the  dreams  of 
avarice,  and  immortal  as  the  gods.  But  the  chemist  made  this  discovery  of 
more  importance  to  the  condition  of  the  human  race  than  that  of  Colum- 
bus, because  by  it  he  gave  man  a  kingdom  different  from  any  that  could 
have  been  his  by  merely  discovering  what  already  existed  upon  earth. 
That  is  the  wonder  of  the  chemist's  work;  he  finds  that  which  is  not  upon 
the  earth  until  he  discovers  it;  just  as  the  artist  creates  so  does  the  chemist. 
If  he  did  not,  there  would  be  no  chemical  industry  to  write  about. 

Experiment  to  Manufacture 

Having  investigated  this  acid,  he  found  it  a  most  valuable  new  tool 
with  which  many  new  and  interesting  things  could  be  made,  and  much 
could  be  done  that  before  had  been  impossible.  It  became  necessary,  then, 
if  all  men  were  to  profit  as  the  chemist  always  wishes  them  to  do  by  his 
power,  that  sulfuric  acid  should  be  made  easily  and  cheaply  in  large 
quantities.  The  first  attempt  at  commercial  manufacture  was  in  1740; 
before  that  each  experimenter  made  what  little  he  needed  for  himself. 
The  process,  that  mentioned  above,  was  carried  out  in  large  glass  bal- 
loons. It  was  a  costly  method  and  tedious.  Then  in  1746  lead  chambers 
were  substituted  for  the  glass  and  the  industry  progressed  rapidly. 


The  whole  object  of  this  most  basic  of  all  chemical  industries  can  be 
written  in  three  simple  little  equations. 

Sulfur  Oxygen  Sulfur  Dioxide 

S  +         O2  =  SO2 

Sulfur  Dioxide  Oxygen  Sulfur  Trioxide 

502  +         O2  =  SO3 
Sulfur  Trioxide             Water               Sulfuric  Acid 

503  +       H20  =  H2S04 

Of  the  three  elements  necessary,  oxygen  occurs  uncombined  in  the 
air  of  which  it  forms  one-fifth  by  volume;  it  is  also  present  combined  with 
other  elements  in  very  large  quantities  in  water,  sand,  and  generally 
throughout  the  earth's  crust,  which  is  nearly  half  oxygen  in  a  com- 
bined condition. 

The  Raw  Materials 

The  great  storehouse  of  hydrogen  on  the  earth  is  water,  of  which  it 
forms  one-ninth,  by  weight.  Sulfur  is  not  so  widely  distributed  in  large 
quantities  but  it  is  very  prevalent,  being  present  in  all  plants  and  animals 
and  also  in  such  compounds  as  Epsom  salts,  gypsum,  and  Glauber's  salt. 
In  the  free  condition,  i.e.,  as  sulfur  itself,  it  is  found  in  volcanic  regions 
and  also  where  bacteria  have  produced  it  by  decomposing  the  products  of 
plant  decay.  There  is  one  other  source  of  sulfur  that  is  quite  important, 
a  compound  with  iron  which  contains  so  much  sulfur  that  it  will  burn. 

The  problem  then  was  to  take  these  substances  and  from  them  group 
the  elements  in  such  order  as  to  produce  sulfuric  acid. 

Since  sulfur  burns  readily,  that  is,  unites  with  oxygen  to  form  sulfur 
dioxide,  one  might  expect  it  to  take  up  one  more  atom  of  oxygen  from  the 
air  and  become  sulfur  trioxide.  It  does,  but  so  slowly  that  the  process 
would  never  suffice  for  commercial  production.  But  there  is  a  way  of 
speeding  up  the  reaction  which  depends  on  using  another  molecule  as  a 
go-between,  thus  making  the  oxygen  more  active.  The  principle  is  that 
of  the  relay.  Suppose  an  out-fielder  has  to  throw  a  ball  a  very  long  way. 
The  chances  are  that  the  ball  will  not  be  very  true  and  that  it  may  fall 
short  of  reaching  the  base.  If  there  is  a  fielder  between,  he  can  catch  the 
ball  and  get  it  to  the  base  with  much  greater  energy. 

The  chemist  uses  as  a  go-between  a  catalyst  (in  one  process),  oxides  of 
nitrogen.  Molecules  of  this  gas  throw  an  oxygen  atom  directly  and  un- 
failingly into  any  sulfur  dioxide  molecule  they  meet,  then  equally  cer- 
tainly they  seize  the  next  oxygen  atom  that  bumps  into  them  and  are 
ready  for  the  next  sulfur  dioxide  molecule.  Since  molecules  in  a  gas 


mixture  bump  into  each  other  roughly  five  billion  times  a  second,  there 
is  a  very  good  chance  for  the  exchange  to  take  place  in  the  great  lead 
chambers  of  approximately  a  capacity  of  150,000  cubic  feet  into  which  are 
poured  water  molecules  (steam),  oxygen  molecules  (air),  and  sulfur 
dioxide,  to  which  are  added  small  quantities  of  the  essential  oxides  o£ 

The  Acid  Rain 

A  corrosive,  sour  drizzle  falls  to  the  floor  and  this  is  chamber  acid. 
It  is  sold  in  a  concentration  of  70  to  80  per  cent.  The  weak  chamber  acid 
is  good  enough  for  a  great  many  industrial  purposes  and  is  very  cheap. 
If  it  is  to  be  concentrated  this  must  be  done  in  vessels  of  lead  up  to  a 
certain  concentration  and  then  in  platinum  or  gold-lined  stills  if  stronger 
acid  is  needed.  Naturally  this  is  expensive  and  every  effort  was  made  to 
find  a  method  of  making  strong  sulfuric  acid  without  the  necessity  of 
this  intermediate  step.  Especially  was  this  true  when  the  dyestuffs 
industry  began  to  demand  very  large  quantities  of  tremendously  strong 
sulfuric  acid  which  was  not  only  100  per  cent  but  also  contained  a  con- 
siderable amount  of  sulfur  trioxide  dissolved  in  it  (fuming  sulfuric  acid). 

The  difficulty  was  overcome  by  using  another  catalyst  (platinum)  in 
the  place  of  the  oxides  of  nitrogen.  If  sulfur  dioxide  and  oxygen  (air) 
are  passed  over  the  metal  the  two  gases  unite  to  form  sulfur  trioxide  much 
more  rapidly  and  in  the  absence  of  water.  Since  platinum  is  very  expensive 
and  its  action  depends  on  the  surface  exposed,  it  is  spread  on  asbestos 
fibers  and  does  not  look  at  all  like  the  shiny  metal  of  the  jeweler.  This 
method  is  known  as  the  contact  process  and  the  product  is  sulfur  tri- 
oxide, which  represents  the  highest  possible  concentration  of  sulfuric  acid 
and  can  be  led  into  ordinary  oil  of  vitriol  (98  per  cent  sulfuric  acid)  and 
then  diluted  with  water  and  brought  to  98  per  cent  acid  or  left  as  fuming 
acid,  depending  on  the  requirements  of  the  case.  The  perfection  of  this 
process  was  the  result  of  some  very  painstaking  research  because  when  it 
was  tried  at  first  it  was  found  that  the  platinum  soon  lost  its  virtue  as  a 
catalyst,  and  it  was  also  discovered  that  the  reason  for  this  was  the 
presence  of  arsenic  in  the  sulfur  dioxide.  To  get  rid  of  every  trace  of 
arsenic  is  the  hardest  part  of  the  contact  process. 


Next  time  you  visit  a  laboratory  ask  to  be  shown  a  bottle  of  concen- 
trated sulfuric  acid.  You  will  see  a  colorless,  oily  liquid,  much  heavier 
than  water,  as  you  will  notice  if  you  lift  the  bottle.  A  little  on  your  skin 


will  raise  white  weals  and  then  dissolve  your  body  right  away;  paper  is 
charred  by  it  as  by  fire.  When  it  touches  water  there  is  a  hissing. 

Sulfuric  Acid  and  Civilization 

A  dreadful  oil,  but  its  importance  to  industry  is  astonishing.  If  the  art 
of  making  it  were  to  be  lost  tomorrow  we  should  be  without  steel  and 
all  other  metals  and  products  of  the  metallurgical  industry;  railroads, 
airplanes,  automobiles,  telephones,  radios,  reenforced  concrete,  all  would 
go  because  the  metals  are  taken  from  the  earth  by  using  dynamite  made 
with  sulfuric  acid;  and  for  the  same  reason  construction  work  of  all 
kinds,  road  and  bridge  building,  canals,  tunnels,  and  sanitary  construction 
work  would  cease. 

We  should  have  to  find  other  ways  to  produce  purified  gasoline  and 
lubricating  oil.  The  textile  industry  would  be  crippled.  We  should  find 
ourselves  without  accumulators,  tin  cans,  galvanized  iron,  radio  outfits, 
white  paper,  quick-acting  phosphate  fertilizers,  celluloid,  artificial  leather, 
dyestuflfs,  a  great  many  medicines,  and  numberless  other  things  into  the 
making  of  which  this  acid  enters  at  some  stage. 

If  at  some  future  date,  however,  all  of  our  sulfur  and  all  of  our  sulfur 
ores  are  burned  up  the  chemist  will  yet  find  ways  of  making  sulfuric  acid. 
Possibly  he  may  tap  the  enormous  deposits  of  gypsum  which  exist  in  all 
parts  of  the  earth.  This  has  been  done  to  some  extent  already  but  is  not 
a  process  which  is  cheap  enough  to  compete  with  sulfuric  acid  made 
from  sulfur. 


It  is  essential  that  all  the  heavy  chemicals,  that  is,  the  most  used  acids, 
alkalies,  and  salts,  should  be  made  so  far  as  possible  from  readily  available 
cheap  material.  We  use  air,  water,  and  abundant  minerals  on  this  account. 
Nitric  acid  caused  the  chemical  industry  much  concern  until  it  was  found 
possible  to  make  it  from  air,  because  until  then  its  source  was  Chile 
saltpeter,  or  sodium  nitrate,  a  mineral  occurring  in  a  quantity  only  in  the 
arid  Chilean  highlands.  However,  this  source  of  supply  is  still  the  most 
important  and  the  process  used  is  one  of  great  interest. 

Having  made  oil  of  vitriol,  the  chemist  found  that  he  could  produce 
other  acids,  one  of  the  most  important  of  these  being  liberated  from  salt- 
peter by  the  action  of  sulfuric  acid.  When  nitric  acid  is  made  in  this 
fashion  we  find  that  the  sulfuric  acid  is  changed  into  sodium  sulfate  and 
remains  behind  in  the  still.  One  might  think  from  this  that  sulfuric  acid 
is  stronger  and  on  that  account  that  it  drives  out  nitric  acid,  but  in  fact 


this  preparation  depends  on  a  very  simple  principle,  one  of  great 

Another  Dance 

We  may  best  illustrate  it  by  returning  to  our  former  simile.  Let  us 
assume  a  sodium  nitrate  juggler  moving  rather  slowly.  He  is  bumped 
into  by  a  sulfuric  acid  juggler  moving  at  about  the  same  rate.  They 
exchange  some  of  the  atoms  with  which  they  are  playing  and  in  conse- 
quence one  juggler  holds  sodium  hydrogen  sulfate  while  the  other  holds 
nitric  acid. 

NaN03  +  H2S04  -»  NaHSO4  +  HNO3 

The  nitric  acid  molecule  does  not  slow  down  the  juggler  as  much  as 
the  sodium  hydrogen  sulfate  and  therefore  this  particular  dancer  moves 
away  quite  fast.  Suppose  millions  of  these  exchanges  to  be  taking  place; 
then  the  nitric  acid  molecules  will  continue  to  dance  away  and  will  not 
come  back  to  exchange  their  atoms  any  more.  If  we  keep  them  all  in  by 
putting  a  lid  on,  then  they  are  forced  to  go  back  and  we  get  no  more 
than  a  sort  of  game  of  ball  in  which  the  hydrogen  and  sodium  atoms  are 
passed  back  and  forth.  If,  on  the  other  hand,  we  open  the  lid  and  put  a 
fire  under  the  pot,  the  nitric  acid  molecules  move  faster  and  sooner  or 
later  all  of  them  are  driven  out. 

Nitric  acid  is  now  made  from  the  air  in  more  than  one  way  so  that 
we  are  entirely  independent  of  the  beds  of  Chile  saltpeter  no  matter  what 
might  happen  to  them.  Without  nitric  acid  we  could  not  make  gun- 
cotton,  dynamite,  TNT,  picric  acid,  ammonium  nitrate,  and  the  other 
explosives  which  are  so  enormously  important  to  our  civilization.  In  addi- 
tion, we  would  lose  all  our  brilliant  dyes  and  most  of  our  artificial  silk, 
from  which  it  is  easy  to  see  that  this  substance  is  of  great  importance  to 
all  of  us. 



Among  the  treasures  to  which  man  fell  heir  as  the  most  important 
inhabitant  of  the  earth  was  one  of  innumerable  little  cubes  made  of 
sodium  and  chloride,  crystals  of  salt.  These  he  noticed  whenever  seawater 
evaporated  and  he  soon  found,  if  he  lived  on  a  vegetable  diet  as  he  did  in 
some  places,  that  the  addition  of  these  to  his  food  made  it  much  more 
pleasant  and  savory.  It  fact,  it  is  a  necessity  for  the  health  of  the  human 
body,  Hunting  peoples  do  not  use  it  so  much  because  they  live  almost 


entirely  on  meat,  which  contains  sufficient  salt.  Next  it  was  found  that 
salt  could  be  employed  for  preserving  fish  and  meat,  and  thus  man  was 
able  to  tide  over  the  periods  in  which  hunting  was  poor.  For  ages  and 
ages  it  was  put  to  no  other  use.  Nobody  but  a  chemist  would  have  thought 
of  doing  anything  with  it.  In  order  to  understand  the  whole  of  what  he 
did  and  the  part  which  salt  plays  in  industry  owing  to  the  chemist's 
activity  we  must  go  back  a  little. 

Soap  as  a  Hair  Dye 

Very  early  it  was  found  that  the  ashes  of  a  fire  (and  fires  at  that  time 
were  always  made  of  wood)  were  useful  in  removing  grease  from  the 
hands.  They  were  the  earliest  form  of  soap  and  it  is  surprising  how  long 
they  remained  the  only  thing  used.  Our  records  go  to  show  that  the 
Romans  were  the  first  of  the  more  civilized  peoples  to  find  out  how  to 
make  real  soap,  and  they  learned  it  from  the  Gauls,  who  used  the  ma- 
terial which  they  made  from  wood  ashes  and  goat's  tallow  for  washing 
their  hair  and  beards  because  they  believed  that  this  gave  them  the 
fiery  red  appearance  which  they  thought  was  becoming.  The  Romans 
saw  the  advantage  of  soap  over  wood  ashes  and  a  very  considerable  trade 
in  the  making  of  various  kinds  of  soaps  arose,  but  the  difficulty  always 
was  with  the  production  of  the  ashes  because  it  takes  quite  a  lot  of  ashes 
to  make  even  a  small  quantity  of  soap.  The  advantage  of  having  some- 
thing more  abundant  to  take  the  place  of  the  ashes  was  evident.  But 
the  real  stimulus  which  led  to  the  discovery  of  soda  ash  came  from  a 
different  source. 

Glass  from  Ashes  and  Sand 

It  was  found  that  ashes  heated  with  sand  formed  glass.  It  was  also 
found  that  the  ashes  of  marine  plants,  or  plants  occurring  on  the  seashore, 
gave  a  much  better  glass  than  that  which  could  be  made  from  the  ashes 
of  land  plants.  In  consequence  of  this,  as  the  art  of  glass  making  grew, 
barilla,  the  ashes  of  a  plant  growing  in  the  salt  marshes  of  Spain,  became 
an  increasingly  important  article  of  commerce  and  upon  it  depended  the 
great  glass  factories  of  France  and  Bohemia.  Owing  to  the  political 
situation  which  arose  at  the  end  of  the  eighteenth  century,  France  found 
herself  in  danger  of  losing  her  supremacy  in  the  art  of  making  glass 
because  England  cut  off  her  supply  of  the  Spanish  ashes.  For  some  reason 
the  French  ruler  at  the  time  had  vision  enough  to  see  that  it  might 
be  possible  to  make  barilla  artificially  from  some  source  within  the 
kingdom  of  France  and  he  offered  a  prize  to  any  one  who  would  make 
his  country  independent  of  Spain.  We  have  seen  that  the  chemist's  busi- 


ness  is  the  transmutation  of  one  kind  of  material  into  another,  and 
naturally  it  was  the  chemist  who  came  forward  with  a  solution  of  the 
problem.  Since  this  process  is  now  supplanted  by  a  more  economical  one, 
we  will  merely  outline  it  here. 

Limestone  to  Washing  Soda 

Remember  that  it  is  essential  to  start  from  some  abundant  common 
material.  Le  Blanc,  the  chemist  who  solved  the  problem,  knew  that  the 
Spanish  ashes  contained  sodium  carbonate,  the  formula  of  which  we 
write  as  Na2COs;  that  is,  it  is  a  combination  of  sodium,  carbon,  and 
oxygen.  There  are  a  great  many  carbonates  in  nature  and  among  these 
is  that  of  calcium  which  we  know  as  chalk,  limestone,  or  marble,  depend- 
ing on  the  way  in  which  it  crystallizes.  In  this  we  have  a  substance  of  the 
formula  CaCOa.  Suppose,  then,  we  write  the  two  compounds  side  by  side: 
Na2COa,  CaCOa.  Evidently  the  only  difference  is  that  in  one  we  have  two 
atoms  of  sodium  (Na2)  in  place  of  one  of  calcium  (Ca)  in  the  other. 
Salt  contains  sodium  and  is  very  common.  If,  then,  we  can  get  the  sodium 
radical  from  the  sodium  chloride  and  the  carbonate  radical  from  the 
limestone  and  join  the  two  pieces  we  will  get  sodium  carbonate,  which 
is  what  we  want.  What  Le  Blanc  did  was  to  treat  sodium  chloride  with 
sulfuric  acid.  This  gave  him  sodium  sulphate  and  hydrochloric  acid.  Then 
he  heated  the  sodium  sulfate  with  coke  or  charcoal  and  limestone,  after 
which  he  extracted  the  mass  with  water  and  found  that  he  had  sodium 
carbonate  in  solution. 

The  steps  do  not  sound  difficult  but  it  was  really  a  great  feat  to 
make  them  commercially  possible.  In  the  first  stage  when  sulfuric  acid 
acted  on  the  salt,  hydrochloric  acid  was  given  off  and  this  was  a  great 
nuisance.  The  amount  of  it  produced  exceeded  any  use  that  could  be 
found  for  it  and  it  was  poured  away;  being  highly  acid  it  undermined 
the  houses  in  the  neighborhood  and  caused  a  great  deal  of  trouble.  Later, 
it  became  the  most  valuable  product  of  the  process  because  it  was  con- 
verted into  bleaching  powder  by  a  method  that  we  will  take  up  subse- 

Industry  a  Result  of  Chemical  Discovery 

It  is  interesting  to  learn  that  this  process  which  France  invented  in  her 
extremity  became  one  of  the  largest  industrial  developments  in  England. 
It  caused  the  flourishing  there  of  the  sulfuric  acid  industry  because  this 
acid  was  necessary  for  the  process  and,  as  we  have  seen,  sulfuric  acid  is 
tremendously  valuable  in  a  great  variety  of  directions.  It  also  made 
possible  the  development  of  an  enormous  textile  industry  because  the 


making  of  cloth  needs  soap  and  bleach,  both  of  which  were  first  supplied 
in  abundance  as  a  consequence  of  Le  Blanc's  discovery. 

To  return  to  the  story  of  the  chemist's  transformations  of  salt,  the 
present  process  for  the  conversion  of  this  compound  into  sodium  car- 
bonate is  by  the  action  of  ammonia  and  carbon  dioxide  upon  a  saturated 
solution  of  it,  the  carbon  dioxide  being  obtained  from  limestone.  When 
these  three  substances  are  brought  together  a  change  takes  place  which 
can  best  be  described  by  the  following  equation: 

Carbon  Ammonium 





NH3         + 

H20      + 


=     NH4  HCO3 








NaCl     + 

NH4  HCO3     = 


+        NH4  Cl 

The  change  that  takes  place  depends  on  the  fact  that  sodium  bicarbonate 
is  comparatively  insoluble  and  separates  out.  It  is  collected  and  then 
heated,  the  heat  causing  it  to  turn  into  sodium  carbonate,  carbon  dioxide, 
and  water. 

2  NaHCO3  =  Na2CO3  +  CO2  +  H2O 

In  this  process  the  essential  thing  is  to  keep  the  ammonia  in  the  system, 
because  it  is  used  over  and  over  again  and,  if  it  escapes,  an  expense  arises 
out  of  all  proportion  to  the  value  of  the  carbonate  which  must  be  sold 
at  a  price  of  about  two  cents  per  pound.  The  ammonia  goes  out  of  the 
reaction,  as  indicated  in  the  equation,  in  the  form  of  ammonium  chloride 
and  this  is  returned  to  the  process  by  allowing  quicklime,  made  by  heating 
limestone  in  kilns,  to  decompose  the  chloride.  The  other  part  of  the 
limestone  (the  carbon  dioxide)  is  also  used  in  the  process,  as  shown  in  the 
first  equation.  We  start  then  with  salt,  water,  and  limestone,  and  we  finish 
with  calcium  chloride  and  sodium  carbonate. 

Caustic  Soda 

This  is  not  all  that  the  chemist  was  able  to  do  with  salt.  In  soap  making 
much  better  results  are  obtained  if,  instead  of  using  wood  ashes  which 
give  us  nothing  but  an  impure  soft  potash  soap,  we  use  sodium  hydroxide 
or  caustic  soda.  Now,  caustic  soda  is  something  which  does  not  occur  in 
nature  because  it  always  combines  with  the  carbon  dioxide  of  the  air  or 
with  some  acid  material  and  disappears.  The  old  method  of  making  it 
was  to  take  the  soda  of  the  Le  Blanc  process  and  to  treat  it  with  slaked 
lime.  In  this  way  we  can  make  about  a  14  per  cent  solution  of  caustic 
soda  which  is  then  evaporated  if  it  is  required  in  a  more  concentrated 


form.  This  method  of  making  caustic  soda  was  sufficiently  economical  to 
give  us  all  that  we  needed  at  very  reasonable  prices,  but  eventually  a 
better  method  was  discovered. 

Caustic  soda  is  NaOH,  that  is  to  say,  it  is  water  (HbO)  in  which  one 
of  the  hydrogens  has  been  replaced  by  sodium.  If  in  any  way  we  could 
make  this  reaction  take  place,  NaClH- HOH  =  NaOH  +  HCl,  we  would 
get  directly  two  products  which  we  want.  Unfortunately,  it  is  impossible 
to  get  salt  to  exchange  atoms  in  this  way  with  water.  However,  a  study 
of  salt  solutions  showed  that  the  atoms  of  sodium  and  chlorine  were 
actually  separated  when  in  solution  and  that  they  also  acquired  a  property 
which  would  allow  of  their  segregation.  They  became  electrically  charged 
and  it  is  always  possible  to  attract  an  electrically  charged  body  by  using 
a  charged  body  of  opposite  sign.  If,  then,  we  put  the  positive  and  the 
negative  pole  of  a  battery  or  another  source  of  electricity  in  a  solution 
of  salt  the  chlorine  will  wander  away  to  the  positive  and  the  sodium 
will  wander  to  the  negative  pole. 


What  takes  place  can  best  be  described  by  a  rough  analogy.  Suppose 
two  automobiles  of  different  makes  are  running  side  by  side,  keeping 
together  because  of  the  friendship  which  exists  between  the  two  parties. 
Now  suppose  these  two  machines  have  an  accident  in  which,  by  a  freak, 
one  wheel  is  torn  off  one  car  and  added  to  the  other.  Assume  that  the 
occupants  of  the  car  are  not  damaged  and  that  the  cars  can  still  run;  also 
that  the  fifth  wheel  is  a  distinct  nuisance.  If  there  were  two  garages  at 
considerable  distances,  one  of  which  specialized  in  taking  off  extra  wheels 
and  the  other  did  nothing  but  put  on  missing  wheels,  and  the  accident 
were  a  common  one  involving  thousands  of  machines,  then  it  would  be 
natural  for  the  cars  to  move  in  opposite  directions  to  these  two  garages 
and  if  we  assume  that  all  the  wheels  are  interchangeable,  then  there 
might  be  a  traffic  between  the  garages,  by  another  road  perhaps,  the 
wheels  being  sent  from  one  to  the  other. 

This  very  rough  picture  is  intended  to  describe  the  fact  that  when  the 
sodium  and  chlorine  atoms  of  salt  are  separated  by  water  the  electrons  of 
which  they  are  composed  are  distributed  in  such  a  way  that  there  is  an 
extra  one  in  the  chlorine  which  (an  electron  being  negative)  makes  the 
chlorine  particle  negative,  while  the  sodium  lacks  one  electron  and  there- 
fore becomes  positive  since  it  was  neutral  before.  The  result,  then,  of 
this  electrolysis  or  use  of  the  electric  current  in  separating  the  charged 
atoms  of  sodium  chloride  (the  ions  as  they  are  called)  is  that  sodium  and 
chlorine  are  given  off  at  the  two  poles.  Now,  chlorine  is  not  very  soluble 


in  water  and  can  be  collected  as  a  gas.  The  sodium,  on  the  other  hand, 
as  each  little  particle  is  liberated,  reacts  with  the  water  about  it  to  give 
hydrogen  and  sodium  hydroxide.  Therefore,  we  have  accomplished  what 
we  set  out  to  do,  only  instead  of  getting  sodium  hydroxide  and  hydrogen 
chloride  we  get  sodium  hydroxide,  chlorine,  and  hydrogen. 


The  success  of  this  method  is  due  to  discoveries  in  another  field  of 
science.  Only  when  Michael  Faraday's  researches  on  the  nature  of  the 
electric  current  made  available  another  source  of  energy  different  from 
heat,  was  it  possible  for  the  chemist  to  carry  out  what  has  just  been 
described;  at  first  only  in  a  very  small  way  but,  as  the  production  of 
electricity  became  more  and  more  economical,  ever  on  a  larger  scale  until 
now  the  industry  is  a  most  important  one. 


So  far  we  have  directed  our  attention  almost  entirely  to  the  sodium 
atom  of  salt;  the  other  part  of  the  molecule,  the  chlorine,  is  also  extremely 
valuable  to  us.  It  used  to  be  set  free  by  oxidizing  hydrochloric  acid  of  the 
Le  Blanc  process  with  manganese  dioxide.  Now,  as  we  have  just  seen,  we 
get  it  directly  from  a  solution  of  salt  by  electrolysis. 

Uses  of  Caustic  Soda 

The  two  servants  which  the  chemist  has  conjured  out  of  salt  by  using 
electricity  are  extremely  valuable,  though  if  they  are  not  handled  rightly 
they  are  equally  as  dangerous  as  they  are  useful  when  put  to  work.  Caustic 
soda  is  a  white,  waxy-looking  solid  which  is  extremely  soluble  in  water 
and  attracts  moisture  from  the  air.  It  is  highly  corrosive,  destroying  the 
skin  and  attacking  a  great  many  substances.  When  it  is  allowed  to  act  on 
cellulose  in  the  form  of  cotton  the  fiber  undergoes  a  change  which  results 
in  its  acquiring  greater  luster  so  that  the  process  of  mercerizing,  as  it  is 
called,  is  valuable  industrially.  The  manufacture  of  artificial  silk  made  by 
the  viscose  method  depends  on  the  fact  that  caustic  soda  forms  a  com- 
pound with  cellulose.  Practically  all  the  soap  manufactured  at  the  present 
time  is  produced  by  the  action  of  caustic  soda  on  fat.  The  by-product  of 
this  industry  is  glycerol  which  is  used  in  making  dynamite.  In  fact,  soda 
is  just  as  important  among  alkalies  as  sulfuric  acid  is  among  acids. 

Uses  of  Chlorine 

Chlorine,  the  partner  of  sodium,  is  a  frightfully  destructive  material.  It 
attacks  organic  substances  of  all  kinds,  destroying  them  completely,  and 
it  also  attacks  all  metals,  even  platinum  and  gold,  though  fortunately,  if 


it  is  quite  dry,  it  does  not  react  with  iron,  and  on  that  account  it  can  be 
stored  under  pressure  in  iron  cylinders.  Although  it  is  such  a  deadly  gas 
if  allowed  to  run  wild,  yet  it  is  extremely  useful  and  its  discovery  has  been 
very  greatly  to  the  advantage  of  the  human  race.  First  of  all,  it  is  employed 
in  the  manufacture  of  bleaching  powder,  a  product  which  enables  the 
cotton  industry  to  work  far  more  intensively  than  it  otherwise  could. 
Formerly  cotton  was  bleached  by  laying  it  on  the  grass,  but  that  is  much 
too  slow  for  our  present  mode  of  life.  In  fact,  we  have  no  room  for  it 
because  it  has  been  calculated  that  the  cotton  output  of  Manchester, 
England,  would  require  the  whole  county  as  a  bleaching  field  and  this  is 
obviously  impossible.  Then  came  the  discovery  that  this  same  compound 
could  be  used  in  purifying  our  water  supplies  of  dangerous  disease-breed- 
ing bacteria  and  this  has  reduced  the  typhoid  death  rate  from  that  of  a 
very  dangerous  epidemic  disease  to  a  negligible  figure.  Now,  whenever 
the  water  supply  of  a  city  is  questionable,  chlorine  is  pumped  right  into 
the  mains  or  else  a  solution  made  from  bleaching  powder  is  used.  Twenty 
parts  of  bleaching  powder  per  million  is  sufficient  to  kill  90  to  95  per 
cent  of  all  the  bacteria  in  the  water.  For  medical  use,  a  solution  of  hypo- 
chlorous  acid,  which  is  the  active  principle  of  bleaching  powder,  has  been 
developed  into  a  marvelous  treatment  for  deep-seated  wounds,  and 
recoveries  which  formerly  would  have  been  out  of  the  question  are  now 
possible.  Chlorine  is  also  used  in  very  large  amounts  in  making  organic 
chemicals  which  the  public  enjoys  as  dyestuffs  or  sometimes  does  not 
enjoy  as  pharmaceuticals  or  medicines. 

All  in  all,  the  products  obtained  from  the  little  salt  cube  are  of  extreme 
necessity  and  importance  to  every  one  of  us  and  their  utilization  shows 
what  can  be  done  when  men  of  genius  devote  themselves  to  the  acquisi- 
tion of  real  knowledge  and  then  translate  their  discoveries  into  commercial 
enterprises  for  the  benefit  of  humanity. 


The  brief  story  for  which  we  have  space  indicates  but  very  dimly  the 
real  interest  and  fascination  the  chemist  has  in  handling  matter.  His 
knowledge  has  increased  to  such  a  point  that  he  can  build  you  a  molecule 
almost  to  order  to  meet  any  specifications.  To  be  without  any  knowledge 
of  chemistry  is  to  go  through  life  ignorant  of  some  of  the  most  interesting 
aspects  of  one's  surroundings;  and  yet  the  acquisition  of  some  knowledge 
of  this  subject  is  by  no  means  hard.  There  are  any  number  of  books  which 
tell  the  story  in  simple  language  if  you  do  not  wish  to  study  the  science 
intensively.  On  the  other  hand,  all  that  you  need  is  a  real  interest  and  a 
willingness  to  think  as  you  read. 

The  Chemical  Revolution 


From  Science  Today  and  Tomorrow 


Grandma  got  by  with  a  new  bonnet  and  a  smear  of  talc  across  her  pretty 
little  nose — but  times  have  changed.  To  make  it  easier  for  modern  beauties 
we  have  assembled  the  Personal  Spectrum  Kit  with  all  related  cosmetics  to 
suit  your  individual  coloring. 

From  an  article  by  Edsd  Ford,  exploiter  of  soy  beans  and  builder  of 
motor  cars: 

Our  engineers  tell  us  that  soy-bean  oil  and  meal  are  adaptable  to  by  far 
the  greater  part  of  the  many  branches  of  the  whole  new  plastic  industry, 
and  that  shortly  we  are  to  see  radio  and  other  small  cabinets,  table  tops, 
flooring  tile  in  a  thousand  different  color  combinations,  brackets  and  sup- 
ports of  a  hundred  varieties,  spools  and  shuttles  for  the  textile  trades, 
buttons  and  many  other  things  of  everyday  use  all  coming  from  the  soy- 
bean fields. 

From  an  address  by  the  director  of  an  industrial  research  laboratory: 

In  1913  the  most  carefully  made  automobile  of  the  day  had  a  body  to 
which  twenty-one  coats  of  paint  and  varnish  were  applied.  By  1920, 
through  scientific  management,  it  was  possible  to  do  a  body-painting  job 
in  about  eleven  days.  In  1923  came  the  first  nitrocellulose  lacquers.  They 
cut  the  time  to  two  days.  Now  a  whole  body  is  made  out  of  metal  and 
coated  with  any  color  in  a  day. 

From  a  German  scientific  magazine: 

Over  twenty-five  years  ago  the  German  chemist  Todtenhaupt  patented 
a  process  to  convert  the  casein  of  milk  into  artificial  wool.  Under  the 
economic  stress  of  the  Ethiopian  war  the  Italians  developed  the  process  and 
by  October  1936  will  produce  several  hundred  thousand  pounds  annually 
of  artificial  wool.  No  one  pretends  that  it  is  indistinguishable  from  natural 



wool.  It  is  still  imperfect,  but  no  more  imperfect  than  were  the  first  fibers 
of  artificial  silk.  It  meets  men's  needs — all  that  can  be  reasonably  de- 

Cosmetics,  soy-bean  products,  lacquers,  casein  "wool" — all  are  "syn- 
thetic," as  the  term  is  somewhat  loosely  used  nowadays.  There  are  thou- 
sands more  like  them,  transformations  of  such  familiar  raw  material  as 
coal,  petroleum,  wood,  slaughterhouse  refuse.  Indeed,  every  article  that  we 
touch  is  a  chemical  product  of  some  kind,  and  many  a  one  has  no  counter- 
part in  nature. 

Despite  a  million  chemical  compounds  known  to  technologists,  despite 
the  manifest  artificiality  of  clothes,  houses,  vehicles,  food — all  the  result  of 
chemical  progress — we  have  made  but  a  beginning  in  the  creation  of  a  new 
environment.  If  the  test  of  a  culture  based  on  science  is  the  degree  of  its 
departure  from  nature — woven  cloth  instead  of  skins,  gas  in  the  kitchen 
instead  of  wood,  electric  lights  instead  of  naked  flames,  rayon  instead  of 
silk — we  are  still  chemical  semi-barbarians. 

It  is  beside  the  mark  to  argue  that  a  culture  consists  of  something  more 
than  plastic  compounds  that  take  the  place  of  wood  and  metal.  Our  society 
is  what  it  is  just  because  the  engineer  and  the  chemist  have  struggled  with 
nature,  torn  apart  her  coal,  her  trees,  her  beauty,  discovered  how  they  were 
created,  and  then  proceeded  to  make  new  combinations  of  their  own.  The 
lilies  of  the  field  and  the  honey  of  the  bee  are  not  in  themselves  sufficient. 
On  every  hand  there  is  synthesis  and  creation — scents,  fabrics,  drugs,  plas- 
tics, metals  like  aluminum,  sodium,  and  a  few  thousand  alloys  that  nature 
forgot  to  make  when  the  earth  was  a  cooling  but  still  glowing  ball,  dyes, 
unmatched  by  any  gleam  in  the  iridescent  feathers  of  a  peacock's  tail,  high 
explosives,  lung-corroding  gases,  talking-machine  records  made  of  carbolic 
acid  derivatives  or  artificial  resins. 

More  than  the  substitution  of  a  synthetic  for  a  natural  product  is  in- 
volved. Buttons  that  look  like  ivory  or  bone  but  are  neither,  fibers  that 
mimic  silk  but  are  better,  automobile  upholstery  that  passes  for  leather 
but  is  a  form  of  guncotton,  photographic  films  that  bring  the  same  screen 
plays  to  tens  of  millions  simultaneously  for  as  little  as  25  cents — these  are 
the  outward  evidences  of  a  breaking  down  of  social  distinctions,  of  a  pro- 
found change  in  life.  Gunpowder  made  all  men  the  same  height,  said 
Carlyle  in  a  fine  but  unwitting  comment  on  chemistry.  The  leveling  is  not 
yet  ended. 

New  industries  came  with  the  rise  of  chemistry,  and  with  them  new 
opportunities  for  the  many.  There  is  a  closer  relation  between  democracy 
and  the  laboratory  than  the  historians  recognize.  The  environment  has 


been  chemically  changed,  and  with  that  change  has  come  a  new  vision  of 
the  social  future.  Is  the  world  ready? 

Already  a  beginning  has  been  made  in  three-dimensional  chemistry.  The 
potentialities  are  infinite,  breath-taking.  Suppose  you  want  something  as 
transparent  as  glass  but  as  strong  as  metal.  A  three-dimensional  chemistry 
may  achieve  it.  There  is  even  the  possibility  that  active  compounds  may 
be  devised — active  in  the  sense  that  they  would  shrink  from  blows  or 
electric  shocks  just  as  if  they  were  alive. 

Much  so-called  synthesis  is  merely  a  transformation  of  some  natural 
product.  Yet  it  is  an  evidence  of  social  and  scientific  progress.  It  was  a  tre- 
mendous step  from  killing  an  animal  and  wearing  its  skin  for  protection 
to  weaving  a  fiber  on  a  deliberately  invented  loom,  and  thus  making  a  soft 
pliable  fabric.  But  the  fibers  were  nature's  after  all. 

Indians  once  froze  on  ledges  of  coal.  Mankind  leaped  ahead  when 
inventors  showed  how  coal  could  be  used  to  raise  steam  and  drive  an 
engine.  But  the  new  conception  of  coal  is  chemical.  It  is  a  conception  of 
cosmetics,  alcohol,  drugs,  strange  artificial  sugars,  a  million  useful  com- 
pounds. So  with  wood.  It  is  no  longer  a  material  out  of  which  tables  and 
chairs  and  houses  are  built,  but  cellulose,  which  can  be  reconstructed  to 
assume  the  form  of  shimmering,  silk-like  filaments,  cattle  fodder,  explo- 
sives. .  .  . 

Perhaps  the  most  imminent  of  all  the  changes  that  the  chemical  revolu- 
tion will  bring  about  will  affect  the  materials  of  engineering.  This  age  of 
power  also  is  the  age  of  steel.  Age  of  rust  would  be  a  better  designation. 
If  it  were  not  for  our  paints  and  protective  coatings  nothing  would  be  left 
of  this  machine  civilization  a  hundred  years  hence.  No  less  an  authority 
than  Sir  Robert  Hadfield  has  estimated  that  29,000,000  tons  of  steel  rust 
away  every  year  at  a  cost  to  mankind  of  $1,400,000,000.  And  this  is  not  all. 
To  produce  every  pound  of  this  metal,  lost  by  conversion  into  oxide,  four 
pounds  of  coal  had  to  be  burned.  The  chemical  revolution  has  already 
ushered  in  the  age  of  alloys,  many  of  then  non-corrosive.  There  are  2000 
of  them,  and  we  have  nardly  begun  to  create  all  that  the  world  needs. 
Parts  of  gasoline  engines  are  now  made  of  aluminum  alloys.  All-metal 
airplanes  have  for  years  been  made  of  duraluminum— a  strong,  tough, 
artificial  metal.  Aluminum  alloys  can  be  made  as  strong  as  steel.  Very 
rapidly  they  are  making  their  way  in  industry. 

What  a  tremendous  amount  of  energy  is  wasted  in  hauling,  lifting,  and 
spinning  unnecessarily  heavy  masses  of  metal!  It  costs  now  5  cents  a  pound 
a  year  to  move  the  dead  weight  of  a  street  car.  Think  of  the  solid  steel 
trains  hauled  by  solid  steel  locomotives,  of  automobiles  made  largely  of 
steel,  of  cranes  that  must  be  made  of  tremendous  size  and  power  to  Hit 


gigantic  masses  of  steel  machinery!  Tradition  has  obsessed  us  with  the 
notion  that  weight  and  strength  are  synonymous.  Gradually  the  metal- 
lurgist is  breaking  down  this  old  conservatism. 

Ten  thousand  years  ago,  indeed  until  very  recently,  the  metallurgist  was 
a  random  smelter  and  mixer  of  metals.  Bronze  was  one  of  his  magnificent 
accidental  discoveries.  But  how  different  today!  With  X-rays  he  peers  right 
into  the  heart  of  a  crystal — for  nearly  everything  in  the  crust  of  the  earth 
is  crystalline — and  sees  how  the  atoms  are  placed.  He  juggles  temperatures 
— relates  them  to  such  properties  as  toughness,  magnetism,  lightness.  He 
makes  a  mixture  of  aluminium,  nickel,  and  copper.  The  result  is  a 
magnet  that  can  lift  a  hundred  times  its  own  weight  or  an  alloy  so  light 
that  stratosphere  balloon  gondolas  are  made  of  it. 

Already  he  has  reached  the  stage  where  he  can  synthesize  a  metal  for  a 
special  purpose.  Suppose  he  were  to  design  and  build  an  alloy  with  five 
times  the  tensile  limit  of  any  we  now  have — not  a  wild  impossibility.  When 
he  succeeds,  "the  art  of  transportation  on  land  and  sea  will  be  revolu- 
tionized and,  unfortunately,  the  methods  of  warfare,"  thinks  Dr.  Vannevar 
Bush  of  the  Massachusetts  Institute  of  Technology. 

Many  of  these  alloys  still  to  be  discovered  will  be  used  in  the  home. 
Wood  as  a  structural  material  is  already  doomed.  Two  centuries  hence  an 
ordinary  white-pine  kitchen  chair  of  today  will  be  treasured  as  an  almost 
priceless  antique.  Quarried  stone  will  be  used  only  for  buildings  near  the 
quarry.  For  the  most  part  our  houses  will  be  cages  of  rustless  alloy  steel, 
around  which  cement  or  some  other  artificial  plastic  material  will  be 

Furniture  will  be  made  of  a  beautiful  synthetic  plastic  material,  a  com- 
bination of  carbolic  acid  and  formaldehyde  discovered  and  first  applied 
industrially  by  a  Belgian  chemist,  Dr.  L.  H.  Baekeland,  which  is  destined 
to  become  so  cheap  that  it  will  compete  with  wood.  The  panes  of  the 
windows  through  which  sunlight  streams  and  the  glassware  that  glitters 
on  the  carbolic  acid-formaldehyde  sideboard  will  be  made  of  a  scratch- 
proof  synthetic  product  of  organic  chemistry  which  will  be  transparent, 
insoluble  in  water,  and  unbreakable. 

Draperies,  rugs,  bed  and  table  "linen"  by  the  year  2000  will  be  tissues 
of  synthetic  fibers.  Washing  will  be  obsolete.  Bedsheets,  tablecloths,  and 
napkins  will  be  thrown  away  after  use.  Draperies  and  rugs  will  not  be 
cleaned,  for  as  soon  as  they  show  signs  of  dirt  or  wear  new  ones  will  take 
their  places.  The  household  of  the  chemical  future  will  probably  spend  no 
more  in  a  year  for  its  fabrics  than  it  does  now  for  mere  laundering.  Hence 
housework  will  be  reduced  to  a  pleasant  minimum  involving  scarcely  more 
than  the  dusting  of  synthetic  furniture  and  the  mopping  of  synthetic  floors. 


Synthetic,  too,  will  be  the  apparel  of  those  who  will  live  this  easy  life, 
Cotton,  silk,  wool,  and  such  fibers  as  linen  will  still  be  spun,  but  only  the 
very  rich  or  the  very  snobbish  will  buy  the  fabrics  into  which  they  are 
woven.  Such  material  will  be  as  unnecessary  as  are  the  expensive  furs  in 
which  fashionable  men  and  women  still  clothe  themselves — mere  survivals 
of  a  picturesque  time  when  animals  had  to  be  skinned  or  clipped  to  make 
a  suit  of  clothes.  Already  the  silkworm  is  doomed  as  an  adjunct  of  indus- 
try. Time  was  when  only  the  worm  knew  how  to  change  the  woody 
tissues,  or  cellulose,  of  a  tree  into  glossy  threads.  Now  the  chemist  converts 
the  tree  into  rayon  and  even  makes  silk,  or  something  very  like  it,  out  of 
coal,  limestone,  and  nitrogen. 

Synthetic  wool  is  a  commercial  reality.  The  achievement  was  inevitable. 
Perhaps  within  ten  years,  certainly  within  twenty,  a  man  will  buy  a  ready- 
made  suit  of  synthetic  wool  as  warm  as  any  now  made  from  natural  wool, 
and  free  from  shoddy,  and  $10  will  be  a  high  price  to  pay  for  it.  Even  the 
most  knowing  sheep  would  be  deceived  by  the  yarn.  There  will  be  the 
same  "feel,"  the  same  fluffiness  and  waviness. 

This  $10  suit  is  almost  attainable  now.  In  the  more  distant  future  syn- 
thetic fibers  still  to  be  evolved  will  completely  revolutionize  tailoring.  The 
cheapest  suit  of  clothes  is  now  stitched.  What  if  machines  do  most  of  the 
sewing  and  if  buttonholes  are  mechanically  formed  and  finished  ?  The  cost 
is  high.  Suppose  we  assign  to  the  chemist  and  the  efficiency  engineer  this 
problem  of  keeping  the  body  warm  and  the  person  presentable.  The  first 
step  is  to  abandon  the  old  tradition  of  durability.  Why  must  even  the 
cheapest  suit  last  at  least  a  year?  Is  not  the  standard  merely  a  heritage  from 
a  time  when  money  was  scarce  and  when  a  suit  of  clothes  simply  had  to 

The  synthetic  chemist  proceeds  to  create  new  fibers.  Cheapness  is  his 
goal.  His  threads  may  be  lacking  in  tensile  strength  and  therefore  in 
durability.  But  the  fabric  into  which  they  are  woven  is  not  intended  to  last 
a  year.  Something  much  cheaper  than  artificial  silk  or  wool  is  produced. 
In  fact,  it  is  so  cheap  that  a  suit  can  be  made  for  a  dollar — a  suit  that  will 
be  as  ephemeral  as  a  butterfly  and  will  be  thrown  into  the  ash  barrel  in 
two  weeks.  .  .  . 

"*  The  synthetically  clad  man  of  the  future  will  surely  nourish  himself  on 
synthetic  food.  Ultimately  even  the  soluble  dish  will  be  regarded  as  an 
interesting  heirloom  of  a  still  fairly  savage  past  when  man  chewed  vege- 
tation which  had  been  boiled  or  baked,  and  actually  killed  and  roasted 
animals  for  the  sake  of  their  proteins.  But  the  year  2000  seems  much  too 
early  a  date  for  the  achievement  of  synthetic  nutriment,  considering  the 
staggering  difficulties  that  the  chemist  must  overcome.  .  .  . 


Jets  Power  Future  Flying 


-1L  a  windswept  forest  fire,  your  oil  burner,  or  a  jet  plane  of  the  future. 

There's  simplicity  in  a  stream  of  speedy  gas  pushing  an  airplane  for- 

Jets  with  their  simple  power  are  revolutionizing  travel  through  the  air 
— for  peaceful  transport  or  for  atomic  war  if  we  fail  in  our  attempt  to  get 
along  with  the  other  peoples  of  the  world. 

Applying  jet  propulsion  to  our  airplanes  is  the  high  priority  task  for 
our  research  laboratories  today.  Already  the  P-8os,  with  turbine-jet  engines, 
have  made  obsolete  the  best  conventional  fighter  planes  with  the  best  in- 
ternal combustion  engines.  Jet  bombers  are  being  flown  experimentally. 
Jet  transport  planes  are  on  the  drawing  boards. 

The  reciprocating,  spark-fired  internal  combustion  engine  feeding  on 
gasoline  (look  under  the  hood  of  your  automobile  to  see  one)  has  a  rival 
that  may  drive  it  out  of  the  air. 


There  are  four  different  types  of  jet-propulsion  units: 

The  turbo-jet  and  turbo-propeller-jet  engines,  which  operate  through 
the  principle  of  the  gas  turbine. 

The  pulse-jet,  used  by  the  Germans  as  the  propulsion  unit  of  the  V-i 
"buzz"  bomb. 

The  ram-jet,  currently  undergoing  rapid  development  for  use  on  guided 
missiles  or  other  highspeed  transportation. 

The  rocket,  most  highly  developed  in  the  German  V-2  weapon. 

Only  the  turbo-jet  and  turbo-prop-jet  engines  rely  upon  gas-turbine- 
driven  compressors  to  compress  the  intake  air.  The  pulse-jet  and  the  ram- 
jet use  oxygen  of  the  air  for  burning  their  fuel,  but  compress  the  air  by 
their  speed.  The  rocket  supplies  its  own  oxygen  and  thus  can  go  outside 
the  atmosphere. 



The  principle  of  the  combustion  gas  turbine  is  not  new,  but  it  makes 
possible  the  development  of  turbo-jet  and  turbo-prop-jet  engines  for  air- 
craft. The  future  of  marine  and  railroad  locomotive  propulsion  will  feel 
its  impact.  History  is  full  of  attempts  to  develop  a  satisfactory  gas  turbine. 
Early  experimenters  were  unsuccessful.  They  were  handicapped  both  by 
lack  of  knowledge  which  would  permit  design  of  efficient  compressors 
and  turbines,  and  by  lack  of  the  proper  materials  of  construction. 


The  wartime  need  for  greater  and  greater  speed  in  aircraft  prompted 
intensive  research  that  before  and  during  the  war  increased  our  knowledge 
of  aerodynamics.  Metals  were  devised  that  would  stand  up  for  extremely 
high  temperatures.  This  made  possible  the  development  of  the  gas  turbine, 
in  the  form  of  the  turbo-jet  engine,  for  aircraft.  This  new  type  of  engine 
is  one  of  the  outstanding  developments  since  the  Wrights  flew  the  first 
heavier-than-air  machines. 

The  design  of  the  combustion  gas  turbine  is  simple.  There  is  only  one 
major  moving  part,  a  rotating  shaft  on  which  is  mounted  an  air  compressor 
and  a  turbine  rotor.  The  compressor  supplies  air  to  the  combustion  cham- 
bers where  fuel  is  burned  continuously  to  increase  the  energy  content 
of  the  compressed  air  by  heating  it.  The  resulting  hot  gases  are  then  ex- 
panded through  a  turbine.  The  turbine  rotor  and  shaft  revolve.  In  the  case 
of  the  turbo-jet  engine,  only  sufficient  energy  is  recovered  by  the  turbine 
to  drive  the  compressor,  and  the  hot  gases  leaving  the  turbine  are  exhausted 
through  nozzles  to  form  the  jet.  The  reaction  to  the  jet  propels  the  air- 
craft as  a  result  of  the  increase  in  momentum  of  the  air  stream  due  to  its 
rise  in  temperature  and  volume  as  it  passes  through  the  unit. 

In  the  prop-jet  engine,  the  greater  part  of  the  energy  available  in  the 
hot  gases  from  the  combustion  chamber  is  recovered  by  the  turbine.  The 
power  thus  available,  over  and  above  that  required  to  drive  the  compressor 
is  utilized  to  drive  an  air  screw  propeller,  in  the  case  of  high-speed  aircraft. 

Great  amounts  of  fuel  and  air  consumed  by  the  gas-turbine  engine  in  de- 
veloping its  great  power  are  astounding.  Philetus  H.  Holt,  a  research  direc- 
tor of  the  Standard  Oil  Development  Co.,  has  figured  that  a  turbo-jet 
engine  developing  4,000  pounds  thrust,  equivalent  to  4,000  horsepower  at 
375  miles  per  hour,  will  require  more  than  4,000,000  cubic  feet  of  air  in  an 
hour.  At  this  rate,  all  the  air  in  a  typical  six-room  house  would  be  exhausted 
in  about  nine  seconds.  Approximately  20  barrels  of  fuel  are  burned  each 
hour — enough  fuel,  if  it  were  gasoline,  to  drive  an  automobile  12,000  miles 
at  a  speed  of  60  miles  per  hour,  or,  if  heating  oil,  enough  to  heat  a  typical 
six-room  house  for  two-thirds  of  a  heating  season. 


Heat  is  released  in  the  combustion  chambers  of  the  turbo-jet  engine  at 
the  rate  of  about  20,000,000  Btu.  per  hour  per  cubic  foot  of  combustion 
zone,  which  may  be  compared  with  a  rate  of  one  to  two  million  Btu.  per 
hour  per  cubic  foot  in  the  case  of  industrial  furnaces.  This  great  develop- 
ment of  power  is  accomplished  with  a  freedom  from  vibration  unknown 
in  reciprocating  engines. 


Where  fuel  economy  is  of  secondary  importance,  the  turbo-jet  engine 
far  surpasses  the  conventional  reciprocating  engine  when  high  speed  at 
present  altitudes  is  necessary,  as  is  the  case  in  fighters,  interceptors,  and  fast 
attack  bombers.  When  pressurized  cabins  are  used  combined  with  turbo- 
jet power  at  very  high  altitude,  fast,  long-range  commercial  transports  will 
be  attractive  to  airlines.  At  altitudes  of  40,000  feet  or  higher  the  turbo-jet 
unit  is  much  more  economical  of  fuel  than  at  low  altitudes. 

Long  flights  of  3,000  miles,  which  presently  take  12  to  14  hours,  will  be 
made  in  six  to  seven  hours.  Equipment  and  pilots  will  do  double  jobs;  pas- 
sengers will  get  there  faster. 

The  turbo-propeller-jet  power  plant  has  the  possibility  of  competing 
directly  with  the  conventional  reciprocating  engine  at  present-day  speeds, 
since  improvements  in  design  should  soon  give  fuel  economy  and  operating 
life  equivalent  to  those  of  the  reciprocating  engine. 

How  soon  will  your  airlines  ticket  give  you  such  flight  ?  Some  estimate 
they  will  come  in  three  years,  others  in  five  years  and  others  still  10  years 
or  longer.  The  rapidity  of  their  introduction,  say  the  engineers,  will  be  in 
direct  proportion  to  the  amount  and  calibre  of  the  effort  expended  in  re- 
search and  development. 

Turbo-jets  will  do  their  job  at  double  the  speeds  of  present  airlines,  but 
aviation  will  turn  to  the  ram-jet  to  surpass  the  speed  of  sound. 

Speeds  twice  the  speed  of  sound,  some  1,400  miles  per  hour,  have  been 
achieved  for  short  flights  by  the  "flying  stovepipe." 

Jap  Kamikaze  "suicide"  planes  sparked  the  post-haste  development  of 
the  ram-jet  to  power  the  Navy's  "Bumblebee"  anti-aircraft  weapon  that 
would  have  been  shooting  them  down  if  the  war  had  lasted. 

The  ram-jet  idea  is  not  new,  although,  like  other  modern  jet  engines,  it 
is  20th  century  in  its  conception.  Rene  Lorin,  a  Frenchman,  proposed  in 
1908  the  use  of  the  internal  combustion  engine  exhaust  for  jet  propulsion, 
and  in  his  scheme  the  engine  did  not  produce  power  in  any  other  way. 
Five  years  later  he  described  a  jet  engine  where  the  air  was  compressed 
solely  by  the  velocity,  or  ram,  effect  of  the  entering  air.  This  is  the  ram-jet. 

The  nickname  of  the  ram-jet,  "flying  stove-pipe,"  describes  what  it  looks 


like.  It  is  a  cylindrical  duct,  with  a  varying  diameter.  The  air  enters  through 
a  tapered  nosepiece  and  it  comes  in  at  a  speed  above  that  of  sound.  The 
ram-jet  is  only  efficient  when  it  goes  through  the  air  at  speeds  higher  than 
the  speed  of  sound,  which  is  about  700  miles  per  hour.  In  the  military 
version  of  the  ram-jet,  it  is  launched  and  brought  up  to  speed  by  rockets 
which  soon  burn  themselves  out  and  give  way  to  the  ram-jet  itself. 

Air  entering  the  tube  when  the  ram-jet  is  in  flight  is  slowed  down  to  be- 
low the  speed  of  sound.  The  air  mixes  with  the  fuel.  The  very  simple  de- 
vice for  doing  this  is  at  present  one  of  the  secrets  in  the  ram-jet,  as  applied 
as  an  anti-aircraft  weapon.  The  diflfuser  in  the  air  duct  stabilizes  the 
flame  and  the  combustion  of  the  gases  increases  very  rapidly  through  the 
duct.  Just  to  the  rear  of  the  ram-jet  the  gases  attain  a  speed  of  up  to  2,000 
miles  per  hour. 

When  supersonic  transportation  of  mail,  express  and  ultimately  pas- 
sengers is  contemplated,  the  ram-jet  offers  a  motor  of  great  promise.  The 
present  military  development  of  this  device  is  by  commercial  and  industrial 
agencies,  under  sponsorship  of  the  Bureau  of  Ordnance  of  the  Navy,  with 
the  coordination  of  the  Applied  Physics  Laboratory  of  the  Johns  Hopkins 
University.  This  development  may  influence  peacetime  transportation  of 
the  future  world. 

In  the  future,  liquid  fuels  that  are  produced  from  petroleum  will  be  made 
to  fit  the  requirements  of  jet  engines.  Particular  fuel  requirements  for  the 
turbo-jet  engine  may  even  bring  kerosene  and  other  distillates  heavier 
than  gasoline  back  into  prominence. 

During  the  war  some  of  the  jet  planes  were  designed  to  burn  kerosene 
while  other  jet  devices  operated  on  hundred  octane  gasoline.  Such  high  oc- 
tane gasoline  was  not  actually  necessary  but  due  to  the  fact  that  much  of 
the  aviation  fuel  in  the  war  areas  was  high  octane,  it  was  used  to  simplify 
the  problem  of  supply. 

If  jet  planes  were  used  in  another  war  emergency,  a  fifth  of  the  U.  S. 
petroleum  refining  capacity  would  be  used  for  making  jet  fuels,  Robert 
P.  Russell,  president  of  the  Standard  Oil  Development  Co.,  estimated  re- 
cently. Designing  of  fuel  that  can  be  used  in  a  variety  of  jet  motors  is  as 
important  as  designing  jet  motors  themselves.  Military  specifications  are 
now  being  considered  that  will  cause  more  of  the  fractions  of  petroleum 
to  be  used  in  making  jet  fuel.  This  may  prove  to  be  one  of  the  most  im- 
portant decisions  affecting  flying  power  for  the  future. 


Science  in  War  and  After 


From  Atoms  in  Action 

JL  of  the  air  is  the  Douglas  ¥-19  bomber  designed  for  the  U.  S.  Army, 
which  made  its  first  flight  early  in  1941.  The  yoton  weight  of  this  great 
plane,  twice  as  heavy  as  the  famous  Atlantic  Clipper  ships,  is  borne  by 
wings  stretching  210  feet  from  side  to  side.  With  11,000  gallons  of  gasoline 
in  its  tanks  to  feed  the  four  thirsty  engines  which  release  2000  horsepower 
each,  this  giant  plane  can  carry  28  tons  of  bombs  to  a  point  3000  miles 
away,  and  return  without  re-fueling. 

Though  the  trend  will  probably  be  toward  even  larger  battleships  of 
the  air,  there  is  a  limit  to  the  weight  of  airplanes  which  can  alight  on 
land.  When  the  yo-ton  bomber  is  on  the  ground  its  entire  weight  must 
be  supported  on  its  wheels,  and  these  are  large  and  unwieldy  in  the 
extreme.  In  fact,  the  only  accident  to  the  first  of  these  great  bombers 
occurred  when  one  of  its  wheels  sank  through  a  macadam  pavement. 
Pontoons  rather  than  wheels  will  avoid  this  problem,  and  it  seems  likely 
that  the  giant  flying  battleships  of  the  future,  if  such  there  must  be,  will 
rest  on  water  when  not  in  the  air. 

The  tremendous  destruction  produced  in  Europe  during  the  present 
war  by  falling  bombs  is  likely  to  lead  one  to  think  that  the  bomber  has 
everything  his  own  way.  This  is  becoming  increasingly  less  true  as  defen- 
sive measures  are  perfected.  Entirely  apart  from  this,  the  bomber  who  is 
trying  to  destroy  an  important  target  is  faced  with  a  difficult  problem  at 
best.  Airplanes  do  not  stand  still  in  the  air,  or  even  travel  in  straight  lines 
when  anti-aircraft  shells  are  bursting  around  them,  and  to  hit  a  target 
five  miles  below  from  a  platform  moving  erratically  through  the  air  at 
400  miles  an  hour  requires  more  than  mere  skill.  It  requires  the  assistance 
of  cleverly  designed  scientific  apparatus — hence  the  great  secrecy  regard- 
ing bomb-sights. 

A  bomb  dropped  from  a  plane  strikes  the  ground  far  ahead  of  the  point 
directly  under  the  position  of  the  plane  when  the  bomb  was  dropped. 



Since  the  bomb  when  released  is  moving  forward  with  the  plane,  usually 
as  fast  as  a  revolver  bullet,  it  falls  to  earth  in  a  broad  parabola.  During  the 
twenty  or  more  seconds  which  elapse  while  it  is  falling,  it  may  travel 
more  than  two  miles  forward.  In  addition,  cross-winds  at  various  levels 
can  in  twenty  seconds  blow  the  bomb  far  to  one  side  or  the  other.  Various 
bomb-sights  have  been  developed  which  enable  the  pilot  quickly  and 
automatically  to  allow  for  these  effects.  These  are  complicated  combina- 
tions of  telescope,  speed  indicator,  and  computing  machine  whose  details 
are  kept  rigorously  secret  by  the  various  powers. 

During  the  first  few  months  of  the  aerial  bombardment  of  Britain  in 
1940  the  German  bombers  seemed  invincible,  but  gradually  the  funda- 
mental truth,  that  for  every  new  offense  there  is  a  satisfactory  defensive 
answer,  has  been  borne  out.  First  came  the  defeat  of  the  day  bomber  by 
the  pursuit  plane,  and  when  losses  during  each  daylight  raid  rose  to  10 
per  cent,  the  Germans  were  forced  to  restrict  bombing  operations  to  the 
hours  of  darkness,  when  pursuit  planes  could  not  find  the  bombers. 

Several  months  passed  during  which  night  bombing  raids  were  the 
most  pressing  problem  facing  the  British,  but  gradually  hints  began  to 
appear  which  indicated  that  a  solution  of  the  night-bomber  problem  was 
imminent.  At  the  end  of  1940  the  Air  Chief  Marshal  announced  that  a 
method  for  frustrating  night  bombers  had  been  found,  and  in  June  of 
1941,  the  basis  of  the  method  was  made  public.  It  was  the  radio-locator, 
and  this,  widely  publicized  as  Britain's  secret  defense  weapon,  gives  an 
excellent  example  of  the  use  of  science  in  defensive  warfare.  As  far  as  an 
enemy  bomber  is  concerned  the  device  is  used  to  turn  night  into  day.  If 
no  light  waves  are  available  to  see  with,  says  the  scientist,  look  around 
for  some  other  type  of  waves. 

Actually  nature  perfected  a  similar  method  of  detecting  night  fliers  long 
before  the  airplane  was  dreamed  of.  For  hundreds  of  years  bats  have 
been  able  to  fly  about  in  pitch-black  caves  without  colliding  with  each 
other  or  with  obstacles  in  their  paths.  Scientists  have  stretched  numerous 
criss-cross  wires  in  a  room,  and  then  darkened  the  room  completely  before 
bats  were  brought  into  it,  yet  when  the  bats  were  released  they  flew 
blithely  about  without  once  striking  against  a  wire. 

Careful  tests  showed  that  the  bats  were  indeed  flying  blind,  for  when 
adhesive  tape  was  placed  over  both  eyes  a  bat  could  avoid  the  wires  quite 
as  well  as  with  its  eyes  uncovered.  Though  the  proverbial  bat  may  be 
blind,  it  can  steer  at  high  speed  quite  as  well  as  any  sharp-eyed  lynx. 

When  adhesive  tape  was  placed  over  the  ears  of  the  bats,  however,  the 


results  were  very  different — the  uncanny  power  disappeared  completely. 
Similarly  were  they  handicapped  if  the  power  of  hearing  was  restored, 
but  their  mouths  were  taped  shut. 

Scientists  found  that  the  bats  were  constantly  broadcasting  high-pitched 
squeaks  during  flight,  sounds  so  shrill  that  only  occasionally  could  an  un- 
usually low  one  be  heard  by  human  ears.  These  sounds  were  quite  audible 
to  the  ears  of  the  bat,  and  could  of  course  be  detected  by  special  micro- 
phones. When  several  bats  were  set  flying  around  a  dark  room  in  which 
only  the  flutter  of  skinny  wings  was  audible  to  the  crouching  scientists, 
the  microphone  detectors  showed  the  air  to  be  filled  with  a  shrill  clamor 
of  very  short  wavelength — a  super-sound  related  to  ordinary  tones  as 
ultra-violet  light  is  related  to  visible  light.  The  human  ear  cannot  hear 
waves  vibrating  faster  than  20,000  times  a  second,  but  the  bat  language 
used  for  aerial  navigation  is  found  to  be  loudest  at  50,000  vibrations  a 

As  a  blind  man  walking  along  a  sidewalk  keeps  tapping  with  his  cane 
to  produce  sounds  which  will  be  reflected  from  walls  and  other  obstacles, 
so  the  bat  keeps  broadcasting  his  shrill  cries  and  these,  reflected  from  other 
bats,  walls,  or  even  wires,  come  back  to  his  sensitive  ears  and  warn  him 
of  danger  ahead. 

Though  these  super-sound  waves  will  do  very  well  for  the  navigation 
of  bats,  or  even  of  boats,  they  would  be  of  little  help  in  steering  airplanes 
in  the  dark,  for  these  waves  move  no  faster  than  ordinary  sound  waves, 
and  we  have  already  seen  that  a  fast  airplane  flies  at  two-thirds  of  this 

Far  more  effective  for  this  purpose,  and  capable  of  being  used  in  the 
same  way  that  bats  use  super-sound,  are  radio  waves.  These  travel  nearly 
a  million  times  as  fast  as  sound  waves,  and  since  airplanes  fly  only  about 
ten  times  as  fast  as  bats,  this  gives  ample  margin,  providing  science  can 
furnish  a  means  of  responding  to  the  reflected  wave  which  is  about 
100,000  times  as  fast  as  the  response  mechanism  of  the  bat.  This  rapid 
response  mechanism  British  scientists  have  been  able  to  develop. 

To  detect  something  with  waves  it  is  necessary  that  the  waves  used  be 
not  much  longer  than  the  object  being  detected.  Therefore,  to  locate  an 
enemy  bomber  having  a  wing  span  of  100  feet,  one  should  use  waves  not 
much  more  than  100  feet  long.  Other  factors  make  still  shorter  waves 
desirable,  and  radio  waves  only  a  few  feet  long,  micro-waves,  are  found 
to  solve  the  problem  admirably. 

What  an  effective  picture  of  the  secret  maneuvermgs  of  science  this 
presents!  Here  we  have  German  planes  loaded  with  destructive  bombs, 
five  miles  up  in  the  air,  swiftly  feeling  their  way  toward  London  by  fol- 


lowing  a  beam  of  radio  waves  sent  from  a  station  behind  them  in  France, 
Such  beam  flying  has  of  course  been  used  for  years,  and  is  a  common- 
place feature  of  most  airlines  in  peacetime.  But  how  is  the  bomber  to 
know  when  to  drop  its  destructive  cargo?  From  Norway  or  some  other 
point  making  a  wide  angle  with  the  first  beam  another  radio  beam  is 
sent,  directed  to  intersect  the  first  beam  directly  over  the  target.  When 
signals  in  his  earphones  tell  the  pilot  that  he  has  reached  this  intersection, 
he  drops  his  load  of  bombs  and  turns  to  streak  for  home.  Scientifically 
designed  murder,  to  be  sure,  but  this  is  not  the  whole  story. 

Scattered  all  over  Great  Britain  are  short-wave  radio  stations  which 
send  beams  of  micro-waves  toward  the  invasion  coast.  When  the  sky 
above  France  is  clear  of  planes  no  waves  are  reflected  to  the  sensitive 
receivers  which  the  British  keep  constantly  on  watch.  But  when  a  plane 
rises  into  the  air  even  100  miles  away,  according  to  news  reports,  it  reflects 
back  some  of  the  micro-waves,  and  thus  can  be  detected  in  ample  time  to 
let  interceptors  take  the  air  and  be  ready  for  it. 

So  important  was  the  radio-locator  that  it  was  officially  given  the  credit 
of  enabling  the  Royal  Air  Force  to  win  the  first  defense  of  Britain.  British 
scientists  had  been  working  on  the  method  for  five  years  or  longer,  and 
scientists  everywhere  are  gratified  that  this  most  spectacular  secret  weapon 
is  of  purely  defensive  value.  The  principle  was  available  to  the  Germans 
and  was  doubtless  known  by  them,  but  this  lessens  its  value  to  the  British 
or  any  other  defending  community  not  one  whit. 


There  are  times  when  a  new  type  of  camera  is  more  important  to  an 
army  than  a  new  type  of  gun,  and  when  a  good  photographer  is  of  greater 
value  than  an  able  sharp-shooter.  Before  and  during  an  intensive  cam- 
paign dozens  of  planes  may  fly  over  the  enemy  lines  every  day  without 
dropping  a  bomb  or  firing  a  shot.  These  planes  contain  complex  oversized 
cameras  with  which  pictures  of  the  terrain  are  taken,  to  detect  any 
changes  in  its  appearance  since  the  previous  flight.  The  eye  of  the  camera 
has  a  great  advantage  over  that  of  any  human  observer,  for  not  only  can 
it  absorb  an  entire  scene  in  a  few  thousandths  of  a  second,  but  it  brings 
back  a  record  of  what  it  saw  which  is  permanent  and  far  more  revealing, 
when  examined  slowly  and  in  detail,  than  the  most  lingering  glance  of 
an  observer  in  an  airplane.  Films  taken  on  two  successive  days  can  be 
superposed  in  such  a  way  that  differences  between  the  two — a  departed 
ship,  a  freshly  bombed  oil-tank,  or  newly  camouflaged  artillery — will 
stand  out  vividly  from  an  unobtrusive  background  of  details  common  to 
both  photographs. 


Reconnaissance  planes  are  as  vulnerable  to  attack  as  any  others,  so  they 
must  fly  as  fast  and  as  high  as  possible.  Great  altitude  requires  provision 
of  giant  cameras,  weighing  several  hundred  pounds  and  costing  more 
than  $5000  apiece,  with  very  large  lenses.  To  take  a  photograph  from  a 
height  of  several  miles  which  will  reveal  details  as  small  as  a  man  requires 
the  use  of  a  lens  consisting  of  four  to  six  carefully  shaped  pieces  of  the 
finest  glass,  each  as  large  as  a  dinner  plate.  Such  a  camera  is,  in  fact,  a 
telescope  of  sufficient  size  to  delight  the  heart  of  almost  any  astronomer. 
To  provide  a  shutter  big  enough  to  cover  such  a  lens,  which  can  yet  open 
and  close  within  a  few  thousandths  of  a  second,  requires  careful  scientific 
designing,  yet  this  is  necessary  if  the  photographs  are  to  be  brilliantly 
sharp  and  clear. 

When  flying  a  reconnaissance  plane,  a  pilot  must  be  prepared  to  level 
off  at  some  definite  height  and  fly  a  long,  straight  course  while  photo- 
graphs are  being  taken.  When  a  red  light  starts  blinking  on  his  instrument 
panel,  the  pilot  knows  that  he  must  fly  the  ship  on  an  even  keel  so  the 
photographer  can  snap  mile  after  mile  of  enemy  territory,  taking  several 
hundred  pictures  on  a  single  roll  of  film.  Automatic  timers  are  sometimes 
used,  which  click  the  shutter  at  any  desired  regular  interval.  It  was  com* 
mon  knowledge  in  1941  that  every  day  hundreds  of  miles  of  the  "invasion 
coast"  of  France  was  thus  photographed  by  the  Royal  Air  Force.  From 
some  of  the  planes  used  for  this  purpose  pictures  were  taken  at  an  altitude 
of  more  than  five  miles.  By  using  multiple  cameras  in  which  each  click 
of  the  shutter  took  nine  pictures  through  as  many  lenses,  an  area  as  great 
as  900  square  miles  was  photographed  with  each  exposure. 

The  greater  the  altitude  from  which  photographs  are  taken,  the  more 
likely  is  the  ground  beneath  to  be  partially  hidden  by  haze.  Light  scattered 
from  this  haze  changes  what  would  otherwise  be  a  crisp  and  vivid  picture 
into  one  of  dull  uniformity  and  low  detail.  Longer  waves  than  those  our 
eyes  can  see  will  be  less  scattered  by  the  haze,  and  for  this  reason  infra-red 
photography  has  become  of  great  importance  in  modern  warfare.  But 
longer  exposures  are  required  when  the  specially  sensitized  film  needed 
for  infra-red  exposures  is  used.  For  this  reason  all  the  armies  of  the  world 
have  been  concerned  with  the  development  of  infra-red  film  of  increased 

As  enemy  territory*  becomes  more  thoroughly  protected  by  fighter 
planes  during  daylight  hours,  it  becomes  increasingly  difficult  to  take  the 
desired  reconnaissance  photographs  each  day.  Therefore,  the  trend  is 
toward  more  night  photography,  when  darkness  lends  to  planes  increased 
safety  from  antiaircraft  fire  and  aerial  pursuit.  Thus  flashlight  photog- 
raphy has  been  brought  into  warfare,  but  flashlights  on  what  a  scale  1 


Instead  of  filling  with  light  a  small  room  or  even  a  huge  auditorium,  the 
flash  must  illuminate  the  whole  of  outdoors! 

To  make  an  area  of  many  square  miles  as  bright  as  day,  even  if  only 
for  an  instant,  army  photographers  have  developed  amazing  flashlights 
which  consist  of  great  sacks  full  of  magnesium  powder,  wafted  slowly  to 
earth  by  small  parachutes.  When  the  photographer  wishes  to  take  a  pic- 
ture, he  merely  tosses  a  sack  of  the  powder  over  the  side  of  his  plane.  The 
parachute  with  which  the  sack  is  provided  opens  automatically,  and  a 
fuse  is  set  off  which  explodes  the  bomb  a  few  seconds  later,  after  the 
powder  has  had  time  to  fall  the  desired  distance  below  the  plane,  and  has 
lagged  sufficiently  behind  it.  A  blinding  flash  of  light  comes  from  the 
exploding  powder,  and  the  first  light  from  this  flash  strikes  a  phototube 
on  the  plane,  and  immediately  opens  the  shutter  of  the  camera.  Events 
are  automatically  timed  so  that  the  shutter  opens  just  as  die  landscape  is 
most  brightly  illuminated. 

Camouflage — the  art  of  concealment  by  merging  an  object  with  its 
surroundings,  or  by  making  it  appear  to  be  what  it  is  not — requires  in- 
creasing cleverness  if  it  is  to  withstand  successfully  the  searching  eye  of 
the  camera.  An  outstanding  example  of  this  occurred  in  July,  1941,  when 
the  British  published  photographs  showing  how  the  Germans  had  at- 
tempted to  mislead  them  into  bombing  an  innocuous  block  of  houses  in 
Hamburg  instead  of  the  great  railroad  terminus  which  the  British  were 
seeking.  A  bridge  over  a  narrow  body  of  water  pointed  directly  at  the 
railway  station,  and  this  the  British  airmen  had  been  using  as  a  landmark. 
The  ingenious  and  industrious  Germans  covered  the  offending  body  of 
water  as  far  as  the  bridge  with  rafts  carrying  false  houses,  and  a  short 
distance  away  installed  a  false  bridge  which  pointed  at  the  block  destined 
for  sacrifice  in  place  of  the  station.  This  device  might  have  succeeded  had 
not  the  superposition  of  photographs  taken  before  and  after  the  alteration 
revealed  the  shift. 

The  stereoscopic  camera,  with  two  lenses  giving  a  pair  of  photographs 
which,  when  viewed  properly,  merge  into  one  which  has  depth  and  a 
lifelike  appearance  of  solidity,  is  especially  valuable  in  revealing  camou- 
flage of  a  common  type.  On  developing  photographs  of  a  certain  enemy 
flying-field,  British  officers  found  that  something  looked  queer  about  a 
group  of  airplanes  packed  closely  in  one  corner  of  the  field.  The  planes 
looked  ordinary  enough  when  viewed  from  the  air,  and  in  the  usual 
photographs,  but  when  a  stereoscopic  camera  was  used  they  appeared 
quite  flat  and  lifeless  in  the  resulting  views,  instead  of  sticking  up  from 
the  ground  as  they  should.  It  is  not  difficult  to  imagine  the  feelings  of  the 
soldiers  who  had  diligently  fitted  together  boards  in  airplane  shapes,  laid 


them  on  the  ground,  and  painted  them,  when  next  day  a  lone  bomber, 
sailing  over  on  the  way  to  deeper-lying  territory,  carefully  dropped  two 
wooden  bombs  on  the  field. 

Of  great  value  in  detecting  camouflage  of  another  sort  is  color  photog- 
raphy, but  strangely  enough,  ordinary  color  photography  often  is  not 
so  useful  as  partially  color-blind  photography.  Certain  commanders  were 
surprised  to  find  that  one  or  two  of  their  aerial  observers  were  able  to 
detect  four  times  as  many  camouflaged  objects  behind  the  enemy  lines 
as  most  of  their  observers  could  see.  Tests  showed  that  the  abnormally 
sensitive  observers  were  color-blind. 

The  explanation  was  not  far  to  seek.  The  camouflaged  objects  had  been 
carefully  painted  by  soldiers  with  normal  vision,  who  had  matched  their 
paints  in  color  with  the  surrounding  green  foliage.  The  color-blind  ob- 
servers, however,  could  not  see  green  anyway.  The  greenness  which,  to 
a  person  of  normal  vision,  obliterated  lesser  differences  between  paint 
and  foliage,  was  eliminated  in  their  eyes,  leaving  contrasts  of  redness  or 
blueness  or  tone  or  shade  to  stand  out  vividly. 

This  discovery  caused  many  articles  to  be  published  stating  that  color- 
blind persons  would  be  in  great  demand  as  aerial  observers.  Such  was  not 
the  case,  for  although  it  is  impossible  to  give  normal  color-vision  to  a 
person  who  is  color-blind,  it  is  quite  easy  to  give  artificial  color-blindness 
to  any  person  with  normal  vision.  All  that  is  needed  is  to  equip  him  with 
a  pair  of  colored  glasses  which  will  absorb  light  of  the  color  he  is  not  to 
see.  A  pair  of  magenta  lenses  will  make  him  green-blind,  for  no  green 
light  can  traverse  them,  while  blue  lenses  will  make  him  red-blind.  Such 
colored  glasses  have  indeed  been  found  of  great  value  in  aerial  observation, 
and  the  really  scientific  camoufleur  should  use  a  spectroscope  to  be  sure 
his  paints  match  the  foliage  for  any  light  waves  that  may  strike  them. 
To  make  the  match  complete  with  surroundings,  he  must  include  the 
invisible  ultra-violet  and  infra-red  waves  as  well  as  those  which  the  eye 
can  see,  for  the  eye  of  the  camera  can  see  several  octaves  of  color,  whereas 
the  human  eye  can  see  but  one.  By  using  the  proper  color  filters  on  his 
scientifically  equipped  camera  the  aerial  photographer  can  ferret  out  any 
object  in  which  all  colors,  invisible  as  well  as  visible,  have  not  been  closely 
matched  with  those  of  the  surroundings. 


The  tank,  introduced  by  the  British  during  the  first  World  War  and 
since  developed  by  other  nations  into  a  formidable  juggernaut,  is  the 
modern  scientific  equivalent  of  the  armored  knight  of  the  Middle  Ages. 
Because  spices  had  to  be  used  instead  of  refrigerants  to  keep  meat  palata- 


ble  in  those  days,  and  because  nothing  was  known  about  balanced  diets 
and  vitamines,  the  medieval  knight  was  rather  a  stunted  fellow  by  mod- 
ern standards.  Most  of  the  suits  of  armor  preserved  in  museums  are  found 
to  fit  men  less  than  five  feet  six  inches  tall. 

Even  the  most  colossal  knight  would  not  have  been  strong  enough  to 
carry  armor  of  sufficient  thickness  to  withstand  modern  high-power 
bullets,  however.  To  be  sure,  he  could  clothe  himself  and  his  staggering 
horse  in  heavy  armor,  but  once  dislodged  he  became  powerless.  What 
more  reasonable  than  to  substitute  an  automobile  for  the  horse,  use  tractor 
treads  to  cover  rough  ground  at  high  speed,  and  put  the  armor  on  the 
resulting  tank  instead  of  on  the  man? 

The  tank,  like  the  airplane,  is  undergoing  a  period  of  rapid  engineering 
development,  with  scientists  concerned  principally  in  making  its  armor 
tougher  and  more  resistant  to  penetration.  The  larger  a  tank  is  made,  the 
more  powerful  can  its  engine  be,  and  the  greater  the  proportion  of  its 
weight  which  can  be  used  for  defensive  armor  and  offensive  armament. 
A  bullet  an  inch  and  a  half  in  diameter  was  formerly  big  enough  to  punch 
holes  in  a  tank,  but  now  shells  three  inches  in  diameter  are  necessary. 
Thus  y-ton  light  tanks  must  give  way  to  25-ton  medium  tanks,  which  in 
turn  retire  before  the  great  80-  and  zoo-ton  tanks  now  being  introduced. 

There  is  a  limit  to  the  concentration  of  weight  which  soil  can  hold, 
however,  and  if  the  weight  of  a  tank  is  to  be  increased  its  treads  must 
cover  a  larger  area.  But  the  larger  the  tank  the  less  strong  does  its  un- 
wieldly  bulk  become.  Like  the  dinosaur,  too  large  a  tank  is  impractical, 
and  may  ultimately  collapse  of  its  own  weight.  For  this  reason  the  battle- 
ship of  the  land  can  never  expect  to  compete  with  the  battleship  of  the 
sea,  which,  like  the  whale,  is  supported  in  depth  as  well  as  in  area.  Land 
tanks  weighing  200  tons  may  become  practicable,  but  to  hold  40,000  ton 
tanks,  a  liquid  is  the  only  suitable  medium. 

On  the  sea,  armor  plate  can  really  come  into  its  own,  and  a  solid  two- 
foot  thickness  of  the  toughest  steel  can  be  used  to  make  an  almost 
impenetrable  barrier.  The  resulting  battleship  spends  most  of  its  life  in 
harbor,  or  cruising  about  merely  existing  as  a  threat  to  lesser  vessels, 
waiting  for  the  few  minutes  or  hours  when  it  may  be  in  action.  Then 
precision  of  fire  is  of  the  utmost  importance,  and  the  fate  of  a  whole  navy 
or  nation  may  depend  on  the  extra  thickness  of  a  hair  by  which  the 
muzzle  of  a  i6-inch  rifle  is  elevated.  The  enemy  is  to  be  struck  if  possible 
before  his  shells  can  strike  back;  no  useful  development  of  science  which 
will  bring  this  about  is  considered  too  expensive. 

Between  1911  and  1941  the  biggest  rifles  used  by  the  navies  of  the 
world  have  swelled  from  12  inches  in  diameter  to  17.  This  has  made 


possible  the  hurling  of  tons  of  steel  28  miles  instead  of  a  mere  n,  with 
a  vast  increase  in  accuracy.  No  navy  expects  to  hit  its  target  at  the  first 
salvo,  which  must  be  considered  as  several  thousand  dollars  spent  to  find 
out  how  the  wind  is  blowing  and  how  accurately  certain  intricate  cal- 
culating machines  have  been  used  to  determine  range  and  direction  of 
aim.  In  the  better  navies  the  target  is  supposed  to  be  struck  on  the  third 
salvo,  but  the  second  is  becoming  increasingly  useful  as  better  scientific 
methods  of  measurement  are  brought  to  bear  on  the  problem. 

To  hit  a  target  30,0000  yards  away  requires  careful  determination  of 
the  speed  of  both  vessels,  the  angles  of  pitch  and  roll  of  the  ship,  the 
barometric  pressure,  the  humidity  of  the  air,  and  even  the  temperature  of 
the  powder  loaded  into  the  gun.  To  introduce  all  these  factors  involves 
extensive  computing  which,  if  done  with  pencil  and  paper,  would  require 
days  to  complete.  Instead,  great  computing  machines  are  used  on  which 
the  temperature  of  the  powder  can  be  set  in  with  one  crank,  humidity 
with  another,  range,  speed,  and  the  rest  of  the  factors  with  others;  then 
the  wheels  turn  and  the  correct  setting  of  the  guns  is  calculated  auto- 
matically within  a  few  seconds. 

Before  the  calculating  machines  can  be  set  into  operation,  careful 
measurements  must  be  made  with  a  dozen  scientific  instruments,  and 
of  these  the  range-finder  is  perhaps  most  interesting.  This  has  the  difficult 
task  of  measuring  the  distance  to  a  target,  which  may  be  anywhere  from 
half  a  mile  to  thirty  miles  away.  A  modern  range-finder  may  contain 
1600  parts  built  with  the  utmost  precision,  and  may  cost  as  much  as 
$40,000.  In  it  are  glass  prisms  whose  sides  are  so  true  that  if  one  were 
extended  a  distance  of  80  miles,  the  line  would  be  within  a  foot  of  its 
correct  course.  A  modern  battleship  is  likely  to  have  at  least  four  of  these 
instruments,  with  two  smaller  ones  pointed  into  the  air  to  determine  the 
heights  of  airplanes. 

There  are  several  types  of  range-finders,  but  most  involve  a  principle 
similar  to  that  involved  in  telling  how  far  away  an  object  is  by  looking 
at  it  with  both  eyes  open.  Look  at  your  finger  held  six  inches  from  your 
nose  and  your  two  eyes  will  be  turned  in  sharply;  now  look  at  something 
far  away,  and  the  eyes  will  turn  so  as  to  look  in  almost  parallel  directions. 

If  human  beings  had  eyes  set  farther  apart  in  their  heads  than  they 
now  are,  we  would  be  able  to  judge  distance  more  accurately  than  we 
now  can.  In  the  range-finder  the  two  eyes  may  be  placed  as  much  as 
thirty  feet  apart,  by  using  prisms  to  bend  the  light  rays.  Two  telescopes 
are  set  into  opposite  ends  of  a  long  tube,  and  the  light  which  comes 
through  these  is  sent  by  prisms  and  lenses  into  the  two  eyes  of  the  ob- 


One  of  the  telescopes  always  looks  straight  ahead,  but  the  other  can 
be  swung  through  an  angle  to  look  at  any  object  at  which  the  other 
telescope  may  be  pointed.  The  observer  sees  his  target  magnified  as  in 
an  ordinary  telescope,  but  everything  above  the  middle  of  the  image  has 
come  through  one  telescope,  and  everything  below  through  the  other. 
He  can  turn  a  handle  until  the  two  parts  of  the  target  come  together  into 
one  well-fitted  picture;  then  both  telescopes  are  pointed  directly  at  the 

The  turning  of  the  handle  also  operates  a  computing  machine,  which 
works  out  the  mathematics  involved  in  finding  how  far  away  an  object  is 
when  the  lines  of  sight  of  the  two  telescopes  make  a  certain  angle.  The  dis- 
tance to  the  target  can  be  read  directly  from  a  dial  which  gives  the  correct 
answer  no  matter  where  the  handle  is  set;  thus  ranges  up  to  40,000  yards 
can  be  read  quickly  to  within  one  salvo  pattern. 

Range-finders  are  usually  placed  high  above  the  deck  of  a  battleship, 
to  enable  them  to  peer  over  the  bulge  of  the  earth  at  distant  objects.  That 
the  guns  are  many  feet  below  the  range-finders,  and  must  be  pointed  high 
into  the  air  rather  than  directly  at  the  target,  while  they  rock  from  side 
to  side  as  the  boat  rolls  and  pitches  on  the  waves,  does  not  disturb  the 
mechanisms  charged  with  the  duty  of  landing  the  first  salvo  close  to  the 

Even  as  early  as  1935  Hitler  had  turned  the  major  attention  of  German 
scientists  to  the  search  for  new  developments  useful  in  war.  As  his  threat 
developed  other  nations  began  tardily  following  suit.  In  Great  Britain 
the  demand  of  the  armed  services  for  physicists  and  chemists  became  so 
great  in  1941  that  these  key  scientists  were  not  permitted  to  enlist  as 
soldiers,  but  were  drafted  for  laboratory  work.  A  great  shortage  of 
trained  scientists  soon  developed  in  all  the  warring  countries. 

Recognizing  that  the  most  powerful  weapons  of  offense  and  defense 
are  furnished  by  science,  the  man  in  the  street,  particularly  in  America, 
has  attempted  to  do  his  bit  as  an  inventor.  Since  1918,  a  Naval  Consulting 
Board  in  Washington  is  said  to  have  received  110,000  letters  containing 
suggestions  for  improvements  in  naval  defense,  and  a  National  Inventors 
Council  was  set  up  by  the  United  States  Government  in  1940,  to  aid 
inventors  who  wished  to  make  suggestions.  Some  of  the  ideas  received 
were  rather  amazing,  but  a  sufficient  number  to  justify  the  effort  of  the 
board  of  experts  who  sorted  them  out  were  said  to  have  merit.  .  .  . 

A  favorite  field  of  amateur  inventors  in  wartime  is  the  "death  ray,"  but 
this  is  a  device  on  which  scientists  waste  no  time  whatever.  All  that  is 


needed  to  make  a  death  ray  usable  is  the  discovery  of  a  suitable  ray. 
None  of  the  agencies  known  to  physicists  at  the  present  time  is  one- 
thousandth  as  effective  in  destructive  action  as  the  shell  or  bomb  con- 
taining a  powerful  explosive,  demolishing  what  it  strikes  by  the  impact 
of  matter  on  matter.  .  ,  . 

Discussion  of  the  responsibility  of  science  for  ills  of  the  human  race, 
of  which  the  miseries  of  war  are  at  present  most  striking,  is  to  a  con- 
siderable degree  academic.  We  cannot  be  rid  of  science  if  we  would, 
for  science  is,  after  all,  nothing  but  knowledge,  and  it  is  doubtful  that 
the  human  race  has  the  ability  to  keep  itself  in  everlasting  ignorance,  even 
if  this  should  be  proved  desirable.  Few  persons  would  argue  that  igno- 
rance is  desirable,  but  many  point  out  that  man's  spiritual  development 
has  not  kept  pace  with  his  material  progress.  This  is  obviously  true,  but 
blame  for  the  situation  can  as  justly  be  attached  to  the  slowness  of 
spiritual  development  as  to  the  rapidity  of  material  progress.  Actually, 
of  course,  the  difficulty  arises  from  the  fact  that  spiritual  development 
comes  only  from  human  experience.  Nature  provides  an  automatic 
compensating  mechanism,  such  that  if  material  progress  is  too  rapid, 
suffering  results  which  accelerates  spiritual  progress. 

Most  of  the  clamor  against  science  arises,  not  from  real  worry  about 
spiritual  development,  but  because  it  is  human  nature  to  take  benefits 
for  granted,  while  complaining  loudly  against  accompanying  disad- 
vantages. It  is  of  value  to  pause  and  note  how  easily  these  disadvantages 
are  exaggerated. 

Much  of  the  horror  of  modern  warfare  arises  from  the  fact  that 
hundreds  of  millions  of  people,  through  the  agency  of  radio,  motion  pic- 
tures, and  the  daily  press,  are  brought  far  closer  in  imagination  to  the 
battlefield  than  was  ever  possible  before.  Though  more  people  do  suffer 
as  a  result  of  warfare  nowadays,  a  larger  proportion  of  them  suffer  only 
mentally  and  in  anticipation. 

Science,  with  its  improved  methods  of  communication,  is  responsible 
for  the  fact  that  the  number  of  things  we  find  to  worry  about  is  increas- 
ing from  day  to  day.  Science  is,  however,  also  responsible  for  the  fact  that 
there  is  an  even  more  rapid  increase  in  the  fraction  of  these  terrible 
things  which  never  happen.  .  .  . 

In  what  are  sometimes  called  "the  good  old  days,"  war,  famine,  and 
pestilence  were  considered  inevitable.  If  half  a  man's  family  was  wiped 
out  in  a  week  by  diphtheria,  that  was  the  will  of  God.  Now  man  has 
made  use  of  his  God-given  opportunities  to  control  famines  which  arise 


from  natural  causes.  Through  science  the  Black  Plague,  cholera,  yellow 
fever,  and  a  dozen  other  pestilences  have  been  wiped  out,  and  the 
rest  are  on  the  way.  The  twentieth  century  may  well  see  war,  this 
further  "pestilence,"  eliminated,  as  through  the  natural  sciences  man 
gradually  raises  the  level  of  availability  of  the  things  he  needs  for  health, 
security,  comfort,  education,  and  enlightenment,  by  creating  more  and 
more  order  in  nature. 

We  hear  much  about  the  "good  old  days,"  but  the  world  is  growing 
older  every  day,  not  younger.  Opportunity  knocks  on  every  hand  for  him 
who  has  ears  to  hear,  and  there  is  ample  evidence  that  the  best  "old  days" 
lie  ahead. 

Edition  of  1941 




A.    THE    RIDDLE    OF    LIFE 

earth,  penetrated  the  atom.  As  yet  we  have  not  touched  the  World  of  Life. 

What  is  this  Life?  In  what  shadowy  spot,  as  yet  unknown,  does  the 
transition  from  the  dead  to  the  quick  take  place?  We  know  many  of  the 
processes  involved  in  living.  We  still  do  not  know  what  life  really  is.  W.  /.  V. 
Osterhout,  the  botanical  scientist  who  has  done  much  to  push  back  the 
borders  of  the  unknown,  opens  our  discussion  with  The  Nature  of  Life.  He 
exposes  many  misconceptions,  although  he  leaves  the  question  unsettled. 
And  yet,  it  is  possible  to  see  how  living  things  exist  in  nature — their  chem- 
ical properties,  actions  and  reactions,  adaptation  to  environment,  develop- 
ment and  multiplication.  That  is  the  theme  of  The  Characteristics  of  Organ- 
isms by  Sir  /.  Arthur  Thomson  and  Patrick  Geddes. 

We  can  also  trace  the  course  of  man's  belief  in  the  spontaneous  origin  of 
life,  especially  as  it  relates  to  the  study  of  the  smallest  living  creatures  under 
the  microscope.  The  study  begins  with  Leeuwenhoek,  Paul  de  Kruif  s  ac- 
count of  the  testy  Dutchman  who,  looking  through  his  homemade  micro- 
scopes, was  the  first  to  see  those  tiny  "animalcules"  which  we  call  microbes. 
The  more  he  looked,  the  more  he  found — in  the  tissues  of  a  whale,  the 
scales  of  his  own  skin,  the  head  of  a  fly,  the  sting  of  a  flea.  He  watched 
them  attack  mussels  and  so  realized  that  life  lives  on  life.  It  is  doubtful 
whether  he  knew  that  life  must  always  come  from  life  or  that  microbes  play  a 
dominant  role  in  disease. 

Those  were  discoveries  that  were  to  take  centuries  and  test  the  abilities 
of  men  like  Spallanzani,  Redi,  Pasteur,  Tyndall,  Koch.  We  no  longer  think 
that  eels  develop  spontaneously  in  stagnant  pools,  that  kittens  (without 



parents)  spring  from  piles  of  dirty  clothes.  The  idea  is  so  foreign  to  us  that 
we  hardly  believe  men  could  have  thought  it  possible.  Yet  the  classic  ex- 
periments which  disproved  once  and  for  all  the  doctrine  of  spontaneous 
generation  were  performed  no  earlier  than  the  last  century  by  Pasteur  and 
Tyndall.  Pasteur  showed  that  water  boiled  in  flasks  to  which  the  dust-filled 
air  was  not  admitted  would  never  generate  life.  He  showed  that  flasks  opened 
in  Paris  contained  numerous  microbes,  while  those  opened  in  the  Jura 
mountains  contained  few  or  none.  "There  is  no  condition  known  today/'  he 
wrote,  "in  which  you  can  afErm  that  microscopic  beings  came  into  the  world 
without  germs,  without  parents  like  themselves." 

Yet  somewhere  along  the  road,  if  we  may  believe  the  latest  researches,  life 
and  nonlife  seem  to  merge.  The  story  is  told  in  Gray's  Where  Life  Begins. 
Here  we  observe  viruses  far  smaller  than  anything  seen  by  Leeuwenhoek, 
made  up  of  molecules  which  may  be  composed  of  thousands  of  atoms. 
Are  they  alive?  It  depends  on  our  definition  of  life.  By  some  standards  they 
are,  by  others  they  are  not.  Perhaps  further  in  the  direction  which  Stanley 
and  others  are  taking,  the  answer  lies. 

The  work  described  in  this  contribution  by  Gray  is  among  the  most 
important  scientific  investigations  of  our  day.  No  matter  what  the  results, 
however,  it  is  doubtful  whether  they  will  resolve  the  conflict  between  the 
mechanists  and  the  vitalists.  The  vitalists  will  continue  to  claim  that  there 
is  something  more  fundamental  than  molecules  and  atoms.  And,  like 
Pasteur  in  the  last  century,  the  mechanists  may  be  counted  on  for  new  facts 
to  meet  each  new  stand  of  their  opponents. 


Plants  and  animals  differ  from  one  another  in  myriad  ways  and  the  most 
obvious  is  that  of  size.  We  do  not  often  stop  to  analyze  this  difference,  as 
Haldane  does  so  amusingly  in  On  Being  the  Right  Size.  Haldane  is  a  famous 
geneticist,  but  he  is  also  a  writer  of  charm  and  wit.  If  you've  ever  been  fear- 
ful that  insects  might  grow  large  enough  to  dominate  man,  or  been  puzzled 
why  mice  could  fall  down  mine  shafts  without  injury,  or  wondered  why  there 
are  no  small  mammals  in  the  Arctic,  here  is  your  answer.  As  there  are  dif- 
ferences, so  are  there  similarities  at  every  level  of  the  plant  and  animal  king- 
dom. One  of  the  most  striking  is  described  in  Parasitism  and  Degeneration 
by  Jordan  and  Kellogg.  From  single-celled  plants  and  animals  to  vertebrates, 
in  amazing  environments  and  through  amazing  metamorphoses,  the  para- 
sites live  on  others;  unable  to  find  a  host,  they  die. 

Next  we  turn  to  the  spectacle  of  life  in  individual  species.  Flowering  Earth 
is  a  long,  full  history  of  the  plant  kingdom.  Donald  Culross  Peattie  traces 
the  steps  from  the  first  single-celled  life  which  appeared  on  earth,  to  the 
algae,  the  Age  of  Seaweeds,  the  first  plants  which  grew  on  land,  the  fern 
forests,  the  conifers  and  cyeads,  and  finally  to  the  modern  floras.  He  tells  us 


about  the  function  of  chlorophyll,  the  breathing  of  plants.  He  shows  how 
even  the  iron  deposits  of  Minnesota  were  formed  by  microscopic  plants. 

T.  H.  Huxley's  Lobster  helps  us  "to  see  how  the  application  of  common 
sense  and  common  logic  to  the  obvious  facts  it  presents,  inevitably  leads  us 
into  all  the  branches  of  zoological  science."  He  shows  us  the  unity  of  plan 
and  diversity  of  execution  which  characterize  all  animals,  whethex  they  swim, 
crawl,  fly,  swing  from  trees  or  walk  the  ground. 

We  travel  from  the  simplest  to  the  highest  in  animal  life,  beginning  with 
The  Life  of  the  Simplest  Animals  in  which  Jordan  and  Kellogg  show  how 
single-celled  animals  eat,  react,  reproduce.  Secrets  of  the  Ocean,  at  high 
and  low  tide,  and  under  the  waves,  are  disclosed  for  us  by  William  Beebe, 
with  sea  worms,  shrimps  and  fishes  playing  roles.  In  The  Warrior  Ants  by 
Haskins  we  see  many  resemblances  to  man's  own  wars,  much  that  we  can 
learn  about  the  human  race.  Ditmars,  known  for  his  work  on  snakes,  and 
his  assistant  Grecnhall  introduce  us  to  one  of  the  most  exciting  of  all  nat- 
uralist adventures  in  The  Vampire  Bat.  (Eckstein  shows  us  the  intelligence 
of  Ancestors,  in  apes  that  pull  ropes  arid  stack  boxes,  that  react  emotionally 
like  men.) 


With  the  great  apes  we  have  reached  a  stage  of  development  which 
approaches  that  of  man,  and  thinking  about  apes  leads  us  inevitably  to  a 
consideration  of  Evolution.  Here  again  is  a  theory  that  has  changed  our 
entire  way  of  thinking  and  in  Darwinisms  we  obtain  a  brief  insight  into  the 
character  of  the  man  who  originated  it.  Darwin  and  "The  Origin  of  Species" 
by  Sir  Arthur  Keith,  points  out  that  Darwin's  masterpiece  is  still  as  fresh 
as  when  it  was  first  written.  Darwin  recognized  that  variation  in  nature  is 
the  means  by  which  natural  selection  can  operate.  How  variation  occurred 
he  did  not  know.  It  remained  for  others  to  analyze  the  problem  further:  de 
Vries  and  Bateson  discovered  that  plants  and  animals  are  subject  not  only  to 
small  variations  but  also  to  large  and  sudden  "mutations."  And  as  a  result 
of  these  inherited  mutations,  new  varieties  are  swiftly  bred. 

It  was  then  that  biologists  rediscovered  the  work  of  a  forgotten  Austrian 
monk.  Hugo  Iltis,  one  of  his  compatriots  now  in  this  country,  describes 
Gregor  Mendel  and  His  Work  with  clarity  and  charm.  These  are  the  basic 
laws  of  modern  genetics.  With  the  discovery  of  the  genes  and  the  chromo- 
somes, further  advances  have  been  made.  Their  function  is  explained  in 
Part  Five,  in  You  and  Heredity  by  Amram  Scheinfeld,  a  selection  that  might 
well  have  been  included  here,  had  its  emphasis  not  been  so  strongly  on  man 

So  much  for  the  main  evolutionary  thread.  But  there  are  important  by- 
ways. Julian  Huxley,  grandson  of  the  great  T.  H.  Huxley  and  himself  a  well- 
known  biologist,  explores  one  of  them  in  The  Courtship  of  Animals,  tracing 
the  influence  of  the  theory  of  sexual  selection  on  our  interpretation  of  ani- 


mals'  development  and  variation.  In  Magic  Acres,  Alfred  Toombs  describes 
amusingly  the  effects  of  the  laws  of  heredity  on  plant  and  animal  breeding. 
Use  of  our  knowledge  has  made  possible  such  experimental  stations  as  that 
at  Beltsville,  Maryland,  "where  the  hens  lay  colored  eggs,  where  the  tomatoes 
sprout  whiskers,  and  the  apples  defy  the  law  of  gravity." 


The  Nature  of  Life 

W.   J.    V.    OSTERHOUT 

From  The  Nature  of  Life 


picture  of  the  evolution  of  the  universe  which  holds  the  imagination 
captive.  Some  of  them  believe  that  all  kinds  of  matter  have  been  evolved 
from  one  original  substance,  hydrogen,  and  that  out  of  the  material  thus 
created  solar  systems  were  built  up.  They  are  able  to  give  us  a  fairly 
satisfactory  description  of  the  processes  which  formed  bodies  like  our 
earth.  Their  account  is  supplemented  by  the  geologist,  who  pictures  the 
progressive  changes  on  the  surface  of  the  earth  whereby  it  became  fitted 
to  support  life.  The  fascination  of  these  researches  is  heightened  when 
we  consider  that  they  lead  directly  to  a  question  of  universal  interest 
which  lies  in  the  province  of  the  biologist,  How  did  life  make  its  appear- 
ance on  our  planet? 

To  this  question  an  answer  was  given  long  ago  by  Lucretius  and  others, 
who  said  that  life  arose  out  of  lifeless  materials.  This  is  known  as  the 
doctrine  of  spontaneous  generation. 

The  adherents  of  this  doctrine  believed  that  life  could  arise  from  non- 
living materials  whenever  the  conditions  were  favorable.  For  a  long  time 
this  belief  found  favor  with  many  thinkers.  But  the  experiments  of 
Pasteur  and  Tyndall  showed  that  if  all  the  living  organisms  in  a  nutrient 
solution  were  killed,  and  if  it  were  kept  free  from  contamination  by 
germs  from  without,  no  life  subsequently  appeared. 

In  spite  of  this  evidence  the  doctrine  of  spontaneous  generation  was 
revived  from  time  to  time.  One  of  the  ablest  botanists  of  the  past  genera- 
tion predicted  that  we  should  one  day  discover  living  forms  too  small  to 
be  seen  by  our  microscopes;  these,  he  said,  represent  the  earlier  steps  in 



the  evolution  of  living  forms  from  lifeless  matter.  This  prediction  has 
been  verified  in  so  far  as  we  now  know  a  considerable  number  of  such 
forms  (filterable  viruses)  some  of  which  cause  important  diseases.  They 
cannot  be  detected  by  the  ordinary  microscope;  they  pass  through  filters 
which  retain  all  the  ordinary  bacteria.  But  we  do  not  think  of  them  as 
lending  support  to  the  doctrine  of  spontaneous  generation,  since  there 
is  no  proof  that  they  can  arise  from  lifeless  material. 

How  then  did  life  originate?  Are  we  not  forced  to  assume  that  some- 
where, at  some  time,  spontaneous  generation  must  have  taken  place? 
Although  no  such  process  appears  to  occur  at  present  we  may  neverthe- 
less suppose  that  in  earlier  geological  epochs  and  under  more  favorable 
conditions  it  might  have  happened.  And  if,  as  Arrhenius  supposes,  life 
can  originate  on  any  appropriate  heavenly  body  •  and  spread  thence  to 
other  bodies  we  have  an  immense  extent  of  time  and  space  in  which  to 
find  conditions  favorable  to  the  origin  of  life.  It  may  be  that  such  condi- 
tions have  never  existed  on  our  planet  and  perhaps  have  occurred  but 
rarely  in  the  history  of  the  universe.  It  is  not  impossible,  however,  that 
we  may  learn  of  their  occurrence,  in  the  past  or  the  present,  since  the 
spectroscope  gives  us  accurate  information  about  the  composition  of 
heavenly  bodies  and,  in  the  case  of  distant  stars,  tells  us  what  they  were 
like  thousands  of  years  ago.  If  we  do  not  observe  on  the  earth  the  con- 
ditions necessary  for  the  origin  of  life  we  may  perhaps  hope  to  find  them 
in  some  of  these  heavenly  bodies  which  might  differ  sufficiently  from 
our  planet  to  provide  the  necessary  combination  of  factors. 

Arrhenius  thinks  that  spores  of  bacteria  might  be  carried  to  the  upper 
limits  of  our  atmosphere  and  thence  be  expelled  into  interstellar  space, 
poetically  called  the  "ether  sea."  There  the  spores  might  be  driven  away 
from  the  sun  by  the  action  of  light,  which  might  exert  on  such  small 
bodies  pressure  sufficient  to  carry  them  to  the  outermost  limits  of  our 
solar  system.  Thus  interstellar  space  might  conceivably  be  peopled  with 
spores  which  could  come  in  contact  with  any  heavenly  body  that  had 
reached  a  stage  in  its  development  at  which  life  could  be  supported. 

It  has  been  objected  that  the  spores  might  be  killed  by  intense  cold, 
dryness,  lack  of  air,  or  the  action  of  light.  But  some  spores  are  resistant 
to  these  influences  and  it  is  by  no  means  certain  that  they  could  not 
survive  a  long  time  in  interstellar  space. 

The  theory  of  Arrhenius  stands  out  as  a  stimulating  example  of  specu- 
lative thought.  It  is  inspiring  to  picture  life,  taking  flight  from  worlds 
outworn  to  fresh  fields  in  younger  planets,  and  persisting  as  long  as  the 
universe  can  harbor  it,  in  cycle  on  cycle  of  endless  progress.  We  may 
admire  this  beautiful  theory  as  a  splendid  achievement  of  the  creative 


imagination  but  we  cannot  at  present  prove  or  disprove  its  correctness. 
If  it  should  one  day  turn  out  to  be  true?  it  will  greatly  widen  the  possi- 
bility of  finding  appropriate  conditions  for  the  origin  of  life. 


Leaving  this  riddle  of  the  origin  of  life,  let  us  turn  to  another  question 
of  equal  importance.  What  new  factor  entered  into  the  universe  with  the 
first  appearance  of  life?  We  may  perhaps  put  this  in  a  more  concrete 
form  by  asking,  How  may  we  distinguish  the  living  from  the  dead? 

It  may  not  seem  very  difficult  to  answer  this  question  but  the  matter 
is  less  simple  than  might  at  first  appear.  As  an  illustration  let  us  take 
some  dry  seeds.  Their  appearance  does  not  tell  us  whether  they  are  alive 
or  dead.  Most  people  if  called  upon  to  decide  would  plant  them,  and 
use  growth  as  a  test  of  life. 

If  we  are  to  employ  growth  in  this  manner  it  is  important  to  have  a 
clear  understanding  of  what  it  means.  Growth  is  often  thought  of  as 
comprising  the  whole  development  of  the  organism.  Ordinarily  the 
life  cycle  of  an  animal  or  plant  begins  with  a  single  cell,  which  by 
repeated  division  produces  a  mass  of  cells.  The  form  of  the  organism 
then  changes,  and  its  parts  become  differentiated  so  as  to  perform  dif- 
ferent functions. 

The  question  now  arises,  What  is  essential  to  the  conception  of  growth  ? 
A  simple  illustration  will  make  it  clear  that  growth  may  go  on  without 
cell  division,  change  of  form  or  color,  differentiation,  or  assimilation  of 
food.  A  small,  spherical,  green  cell,  desiccated  by  the  drying  up  of  a  pool 
in  which  it  has  lived,  and  blown  about  by  the  wind,  eventually  falls  into 
water.  Such  a  cell  often  remains  alive  and  when  it  again  finds  itself  in 
water  begins  to  grow.  No  one  will  deny  that  this  is  genuine  growth  but 
it  certainly  need  not  possess  all  the  features  which  we  have  enumerated. 
In  the  first  place  cell  division  may  be  absent  for  a  long  time.  Many  cells 
increase  enormously  in  size  and  never  undergo  division.  A  nerve  cell 
may  grow  to  be  many  hundred  times  its  original  length  without  divid- 
ing; and  it  will  continue  to  function  for  years  and  finally  die  without 
any  sign  of  nuclear  or  cell  division.  We  cannot  therefore  regard  cell 
division  as  essential  to  the  conception  of  growth,  though  in  most  cases 
it  accompanies  growth  and  is  advantageous  because  it  provides  separate 
compartments  in  which  the  diverse  processes  of  the  organism  can  go  on 
without  mutual  interference. 

There  may  be  no  change  of  form  or  color  in  the  green  cell  of  which 
we  are  speaking,  since  it  may  remain  green  and  spherical  while  growing. 
Nor  is  there  any  reason  to  suppose  that  in  general  a  change  of  form  is 


essential  to  growth.  It  commonly  occurs  but  is  by  no  means  indispensable. 
Nor  is  it  necessary  that  a  differentiation  of  the  organism  into  unlike  parts 
should  take  place  in  order  that  a  process  may  be  called  growth.  Such 
differentiation  is  not  observed  during  the  growth  of  the  simplest  cells, 
such  as  bacteria,  which  may  have  at  the  beginning  all  the  parts  they 
possess  when  growth  is  complete. 

Of  especial  interest  is  the  assimilation  of  food  and  the  building  up  of 
those  substances  which  are  characteristic  of  each  kind  of  organism.  We 
know  that  seeds  can  grow  for  weeks  in  the  dark,  absorbing  nothing 
except  air  and  water.  Under  these  circumstances  the  food  which  is  stored 
in  the  seed  steadily  decreases.  A  kidney  bean  grown  under  such  condi- 
tions may  reach  a  height  of  four  feet  and  gain  in  weight  more  than  fifty 
fold.  Yet  this  great  gain  in  weight  is  wholly  due  to  the  water  it  absorbs. 
Its  dry  matter  steadily  decreases  during  the  whole  period,  undergoing  a 
process  of  combustion  which  results  in  continually  giving  off  carbon 
dioxide  to  the  air.  In  this  way  nearly  half  the  dry  material  may  disap- 
pear during  growth. 

It  is  true  that  growth  must  eventually  cease  under  these  circumstances 
but  the  fact  that  it  can  go  on  for  so  long  although  the  plant  takes  in  no 
food  shows  that  increase  in  dry  weight  is  not  necessary  for  growth. 

Since  we  find  that  growth  may  occur  without  increase  in  dry  weight, 
change  of  form  or  color,  cell  division,  or  differentiation,  we  may  ask, 
What  is  really  essential  to  growth  ?  The  answer  seems  to  be,  An  increase 
in  size  due  to  the  absorption  of  water.  Let  us  now  look  into  this  more 

It  is  a  very  striking  fact  that  when  dry  seeds  are  planted  in  moist  soil 
the  dead  seeds  appear  to  grow  in  the  same  way  as  the  live  ones  during 
the  first  few  hours.  We  find,  however,  that  a  dead  seed  soon  stops 
growing  while  the  living  one  continues.  This  suggests  that  the  water  is 
not  absorbed  in  quite  the  same  manner  in  the  two  cases.  Absorption  of 
water  may  occur  in  two  ways,  which  are  known  as  imbibition  and 
osmosis.  Imbibition  is  the  process  which  occurs  when  a  piece  of  dry 
wood  is  placed  in  water.  The  water  is  taken  up  into  minute  pores,  other 
processes  follow,  and  the  result  is  a  swelling  which,  though  short-lived, 
can  develop  great  pressure.  At  one  time  granite  blocks  were  split  open 
by  drilling  holes  in  a  straight  line  and  inserting  plugs  of  dry  wood.  These 
were  covered  with  wet  rags,  the  wood  absorbed  water  and  the  granite 
block  was  split.  Careful  measurements  show  that  starch  may  develop  a 
pressure  of  thirty  thousand  pounds  per  square  inch  in  taking  up  water. 
It  is  therefore  no  wonder  that  a  ship  loaded  with  rice  is  quickly  burst 
asunder  if  water  reaches  the  cargo. 


In  osmosis  water  is  absorbed  in  a  different  way.  This  may  be  illustrated 
by  the  story  of  the  good  abbe  who  hid  a  skin  of  wine  in  the  cistern  of 
the  abbey.  When  the  monks  developed  an  unusual  taste  for  water  he 
investigated  and  found  to  his  horror  that  the  skin  had  burst.  The  wine 
had  taken  up  water  through  the  skin  because  it  contained  substances 
which  attract  water  (the  word  "attract"  is  here  used  in  a  somewhat 
figurative  sense).  In  the  living  cell  there  is  a  protoplasmic  membrane 
which  corresponds  to  the  skin,  and  inside  this  a  solution  which  attracts 
water.  As  water  is  taken  up  the  protoplasmic  membrane  is  stretched, 
and  if  there  is  a  cellulose  wall  outside  the  living  membrane  it  shares  the 
same  fate.  The  living  membrane  can  be  stretched  almost  indefinitely 
because  the  cell  can  furnish  it  with  new  material  so  that  it  can  continue 
to  expand  without  rupture.  At  the  same  time  the  cell  can  produce 
substances  which  attract  water.  It  is  therefore  possible  for  growth  to 
continue  indefinitely. 

The  growth  of  the  dead  seed  is  due  to  imbibition  while  that  of  the 
living  seed  is  due  during  the  first  few  hours  principally  to  imbibition, 
after  that  principally  to  osmosis.  We  should  therefore  expect  that  the 
dead  seed  would  soon  stop  growing  while  the  living  one  would  continue. 

Osmosis  does  not  ordinarily  develop  so  much  pressure  as  imbibition  but 
it  is  supposed  that  the  pressure  it  produces  in  the  living  cell  may  reach 
three  hundred  pounds  per  square  inch  or  even  more:  this  is  as  much  as 
is  commonly  found  in  steam  boilers.  It  is  sufficient  to  drive  ferns  up 
through  macadamized  roads  and  concrete  sidewalks  and  to  enable  toad- 
stools to  lift  heavy  flagstones. 

Let  us  now  consider  whether  there  is  anything  in  growth  which  can 
be  used  as  a  criterion  of  life.  We  have  tried  first  of  all  to  discover  what 
is  essential  to  growth.  Such  things  as  cell  division,  change  of  form,  dif- 
ferentiation, and  the  assimilation  of  food  may  be  taken  away,  and  yet 
growth  may  go  on  for  a  long  time.  One  process  cannot  be  dispensed  with, 
the  absorption  of  water.  This  appears  to  be  the  essential  thing. 

If  growth  consists  of  the  absorption  of  water  can  this  serve  as  a  test 
to  distinguish  the  living  from  the  dead?  As  we  have  seen,  absorption 
of  water  takes  place  by  imbibition  or  by  osmosis.  Imbibition  cannot 
serve  as  a  mark  of  distinction  for  it  goes  on  in  the  same  way  in  dead  and 
in  living  seeds.  If  we  are  to  employ  growth  as  a  test  of  life  it  can  be  only 
on  the  ground  that  osmosis  is  in  some  way  peculiarly  characteristic  of 
living  cells.  Let  us  see  whether  this  is  the  case. 

One  way  of  attacking  this  question  is  to  attempt  to  make  an  artificial 
cell  which  will  act  like  the  living.  We  may  employ  for  this  purpose  two 
solutions,  A  and  5,  such  that  a  drop  of  A  introduced  into  a  vessel  con- 


taining  B  will  react  with  it  and  form  a  membrane  which  is  impervious 
to  both  A  and  B,  but  is  permeable  to  water.  We  have  now  what  we  may 
for  convenience  call  an  artificial  cell.  It  consists  of  a  membrane  in  the 
form  of  a  rounded  sack  which  completely  incloses  a  drop  of  the  solution 
A  and  which  is  surrounded  by  the  solution  B.  If  now  solution  A  is  more 
concentrated  than  solution  B  water  will  be  attracted  by  solution  A  and 
will  pass  into  the  artificial  cell  which  in  consequence  will  expand  and 
stretch  the  membrane.  Under  the  proper  experimental  conditions  this 
may  continue  for  a  long  time. 

We  may  employ  for  such  experiments  a  great  variety  of  materials,  as 
copper  salts  in  a  solution  of  potassium  ferrocyanide,  metallic  salts  of 
various  kinds  in  a  solution  of  water  glass,  or  tannic  acid  in  a  solution 
of  gelatin.  In  some  cases  the  artificial  membrane  expands  by  repeated 
rupture  and  repair,  in  others  it  is  steadily  stretched  without  rupture,  and 
at  the  same  time  strengthened  by  the  deposit  of  new  material.  The 
protoplasmic  membrane  might  conceivably  expand  in  either  way.  It  is 
not  certain  which  method  is  followed. 

In  both  the  living  and  the  artificial  cell  growth  is  quickened  by  increase 
of  temperature.  In  the  living  cell  there  is  an  upper  limit  of  temperature 
beyond  which  no  growth  takes  place.  This  seems  to  be  due  to  the  proteins 
of  the  living  cell.  If  we  could  employ  such  proteins  in  the  membrane  of 
the  artificial  cell  we  might  obtain  a  similar  result. 

The  rate  of  growth  depends,  in  the  living  as  in  the  artificial  cell  on 
the  supply  of  substances  within  the  membrane  which  can  attract  water. 
In  the  case  of  the  living  cell  these  are  mostly  sugars,  organic  acids,  salts, 
and  so  on,  and  we  can  employ  these  same  substances  in  the  artificial 
cell.  In  the  living  cell  we  often  find  starch,  which  takes  little  part  in 
attracting  water  but  which  may  be  gradually  transformed  into  sugar 
which  attracts  water  actively.  In  the  same  way  we  may  place  starch  in 
the  artificial  cell  and  have  it  slowly  transformed  to  sugar  and  thereby 
cause  the  cell  to  take  up  water. 

If  the  artificial  cell  is  placed  in  a  solution  which  is  more  concentrated 
than  that  inside  the  cell,  water  is  attracted  from  the  cell  to  the  outside 
solution  and  in  consequence  the  cell  shrinks.  This  is  also  true  of  the  living 
cell.  If  it  is  growing  in  tap  water  it  can  be  made  to  shrink  by  putting 
it  into  a  sugar  solution  which  withdraws  water.  If  replaced  in  water  it 
again  expands.  Since  we  regard  this  as  growth,  the  shrinkage  may  be 
looked  upon  as  the  reversal  of  growth.  We  find  that  many  living  cells 
may  be  made  to  grow  and  shrink  several  times  in  succession,  just  as  in 
the  case  of  the  artificial  cell. 

If  the  outside  solution  is  concentrated  enough  to  draw  water  out  of 


the  cell  it  may  nevertheless  prevent  water  from  going  in  and  so  check 
growth  in  proportion  to  its  concentration.  Consequently  by  varying  the 
concentration  we  may  accurately  control  the  rate  of  growth. 

We  might  go  on  to  discuss  other  points  of  resemblance  between  the 
growth  of  the  living  and  the  artificial  cell  but  this  hardly  seems  neces- 
sary. If  we  accept  the  definition  of  growth  given  above  it  is  clear  that 
the  artificial  cell  furnishes  an  imitation  which  is  sufficiently  complete  for 
our  purpose.  We  must  therefore  conclude  that  there  is  nothing  in  the 
absorption  of  water  by  the  living  cell,  either  by  imbibition  or  by  osmosis, 
which  differs  essentially  from  these  processes  as  found  in  non-living 

In  conclusion  we  may  ask  whether  life  can  go  on  in  the  absence  of 
growth.  We  know  that  certain  things  may  be  temporarily  taken  away 
from  living  matter  without  taking  away  life  itself.  Is  growth  one  of 
these?  Certainly  the  resting  seed  lives  for  years  without  any  sign  of 
growth.  This  is  also  true  of  many  animal  cells.  The  suppression  of  all 
signs  of  growth  does  not  in  any  way  involve  the  suppression  of  life. 
Even  when  placed  in  moist  soil  with  all  external  conditions  favorable 
some  living  seeds  remain  quiescent  for  months  or  years  before  they  start 
to  grow. 

Hence  it  seems  possible  to  have  life  without  growth  and  growth  with- 
out life. 

Our  analysis  of  the  process  of  growth  illustrates  the  method  which 
biological  investigation  must  very  commonly  pursue.  The  biologist  wishes 
to  study  living  matter  in  the  same  manner  that  the  chemist  and  physicist 
study  their  material.  His  first  task  is  observation,  after  that  he  must 
analyze  in  order  to  discover  what  properties  are  essential  and  what  are 
merely  accompanying  phenomena.  He  need  not  attempt  to  explain  these 
phenomena,  for,  after  all,  we  can  never  arrive  at  ultimate  explanations. 
But  he  can  attempt  to  predict  and  control.  The  physicist  cannot  explain 
electricity  but  he  can  predict  and  control  electrical  phenomena.  In  the 
same  way  the  biologist  hopes  to  be  able  to  predict,  and  control  life 
phenomena.  One  method  which  he  finds  particularly  useful  is  to  make 
artificial  imitations  which  closely  resemble  the  phenomena  he  is  studying. 
If  he  succeeds  in  this  he  may  find  the  fundamental  laws  of  physics  and 
chemistry  on  which  life  phenomena  are  based. 


The  Characteristics  of  Organisms 


From  Life:  Outlines  of  General  Biology 

apartness  of  living  creatures  from  non-living  things  seems  con- 
spicuous. It  appears  almost  self-evident  that  an  organism  is  something 
more  than  a  mechanism.  But  when  we  inquire  into  the  basis  of  this 
common  conviction  we  usually  find  that  the  plain  man  is  thinking  of  the 
highest  animals,  such  as  horses  and  dogs,  in  which  he  recognises  incipient 
personalities,  in  a  world  quite  different,  he  says,  from  that  of  machines, 
or  from  that  of  the  stars  or  stones.  His  conviction  rests  on  his  recognition 
of  them  as  kindred  in  spirit;  but  he  hesitates  when  we  ask  him  to  consider 
the  lower  animals,  down  to  corals  and  sponges,  and  still  more  when 
we  ask  what  he  thinks  about  plants.  In  such  relatively  simple  organisms 
as  corals  and  seaweeds,  he  detects  no  mental  aspect;  and  apart  from  this, 
they  show  him  but  little  of  that  bustling  activity  which  is  part  of  his 
picture  of  what  "being  alive"  means.  Thus,  while  he  was  sure  that  dog 
and  wheelbarrow  were  separated  by  a  great  gulf,  he  is  not  so  convinced 
about  the  difference  between  a  coral  and  a  stone.  It  is,  therefore,  for  the 
biologist  to  explain  as  clearly  as  he  can  the  fundamental  characteristics  of 
all  living  creatures.  .  .  . 


The  symbol  of  the  organism  is  the  burning  bush  of  old;  it  is  all  afire, 
<iut  it  is  not  consumed.  The  peculiarity  is  not  that  the  organism  is  in 
continual  flux,  for  chemical  change  is  the  rule  of  the  world;  the  charac- 
teristic feature  is  that  the  changes  in  the  organism  are  so  regulated 
that  the  integrity  of  the  system  is  sustained  for  a  longer  or  shorter 
period.  That  excellent  physiologist,  Sir  Michael  Foster,  used  to  say  that 
"a  living  body  is  a  vortex  of  chemical  and  molecular  change";  and  the 



image  of  a  vortex  expresses  the  fundamental  fact  of  persistence,  in  spite 
of  continual  flux. 

Here  it  is  fitting  to  quote  one  of  the  cfassic  passages  in  modern  bio- 
logical literature,  what  Huxley  said  of  the  vital  vortex  in  his  Crayfish 
(1880,  p.  84): 

"The  parallel  between  a  whirlpool  in  a  stream  and  a  living  being, 
which  has  often  been  drawn,  is  as  just  as  it  is  striking.  The  whirlpool  is 
permanent,  but  the  particles  of  water  which  constitute  it  are  incessantly 
changing.  Those  which  enter  it,  on  the  one  side,  are  whirled  around  and 
temporarily  constitute  a  part  of  its  individuality;  and  as  they  leave  it  on 
the  other  side,  their  places  are  made  good  by  new-comers.  .  .  . 

"Now,  with  all  our  appliances,  we  cannot  get  within  a  good  many 
miles,  so  to  speak,  of  the  crayfish.  If  we  could,  we  should  see  that  it  was 
nothing  but  the  constant  form  of  a  similar  turmoil  of  material  molecules 
which  are  constantly  flowing  into  the  animal  on  the  one  side,  and 
streaming  out  on  the  other." 

The  comparison  has  great  force  and  utility;  it  vivifies  the  fundamental 
fact  that  streams  of  matter  and  energy,  such  as  food  and  light,  are 
continually  passing  into  the  organism,  and  that  other  streams  are  con- 
tinually passing  out,  for  instance  in  the  form  of  carbon  dioxide  and 
heat.  On  the  other  hand,  the  comparison  has  its  weakness  and  possible 
fallaciousness;  for  it  is  too  simple.  It  does  not  do  justice  to  the  character- 
istic way  in  which  the  organism-whirlpool  acts  on  the  stream  which  is 
its  environment;  it  does  not  do  justice  to  the  characteristic  way  in  which 
the  organism-whirlpool  gives  rise  to  others  like  itself.  No  one  who  believes 
that  higher  animals  (at  least)  have  a  mental  aspect  that  counts,  can 
agree  that  the  organism  is  exhaustively  described  as  "nothing  but  the 
constant  form  of  a  turmoil  of  material  molecules."  And  even  if  the 
mental  aspect  be  ignored,  there  remains  as  a  fundamental  characteristic 
that  the  "constant  form"  is  secured  by  organic  regulation  from  within. 
Life  is  nothing  if  not  regulative. 

Biology  has  come  nearer  the  crayfish  since  Huxley's  day,  and  it  is 
profitable  to  linger  over  the  fact  that  the  living  creature  persists  in  spite  of 
its  ceaseless  change.  As  a  matter  of  fact  it  persists  because  of  the  self- 
repairing  nature  of  its  ceaseless  change.  Hence  we  give  prominence  to 
this  material  flux. 

METABOLISM  OF  PROTEINS. — Proteins  are  nitrogenous  carbon-compounds 
that  are  present  in  all  organisms,  and,  apart  from  water,  of  which 
there  is  seldom  less  than  70  per  cent.,  they  constitute  the  chief  mass  of 
the  living  substance.  They  are  intricate  compounds,  with  large  mole- 


cules,  which  are  built  up  of  groups  of  amino-acids,  i.  e.  fatty  acids  in 
which  one  of  the  hydrogen  atoms  is  replaced  by  the  ammo-group  NHs 
Proteins,  such  as  white  of  egg,  or  the  casein  of  cheese,  or  the  gluten  of 
wheat,  do  not  readily  diffuse  through  membranes;  they  occur,  as  will 
be  afterwards  explained,  in  a  colloid  state,  and  although  some,  e.  g. 
haemoglobin,  the  red  pigment  of  the  blood,  are  crystallisable,  they  are 
not  known  in  a  crystalloid  state  in  the  living  body.  Though  relatively 
stable  bodies,  proteins  are  continually  breaking  down  and  being  built 
up  again  within  the  cells  of  the  body,  partly  under  the  direct  influence 
of  ferments'  or  enzymes. 

There  are  constructive,  synthetic,  upbuilding,  or  winding-up  chemical 
processes  always  going  on  in  the  living  organism,  which  are  conveniently 
summed  up  in  the  word  anabolism,  applicable,  of  course,  to  the  synthesis 
of  other  carbon-compounds  besides  proteins,  notably  to  the  formation 
of  carbohydrates  in  the  sunned  green  leaf.  There  are  also  disruptive, 
analytic,  down-breaking,  running-down  chemical  processes  always  going 
on  in  the  living  organism,  which  are  conveniently  summed  up  in  the 
word  \atabolism — applicable,  of  course,  to  other  carbon-compounds  be- 
sides proteins,  as,  for  example,  to  the  breaking  down  of  amino-acids  into 
fatty  acids  and  ammonia.  To  include  the  two  sets  of  processes,  anabolism 
and  katabolism,  the  general  term  metabolism  is  used.  It  is  convenient  to 
use  this  term  in  a  broad  way,  as  the  equivalent  of  the  German  word 
"Stoffwechsel"  (change  of  stuff),  to  include  all  the  chemical  routine  of 
the  living  body.  The  present  point  is  that  living  always  involves  the 
metabolism  of  proteins;  and  that  this  is  so  regulated  that  the  living 
creature  lives  on  from  day  to  day,  or  from  year  to  year,  even  from  century 
to  century. 

There  is  intense  activity  of  a  simple  kind  when  the  fragment  of 
potassium  rushes  about  on  the  surface  of  the  basin  of  water,  but  it  differs 
markedly  from  the  activity  of  the  Whirligig  Beetle  (Gyrinus)  that 
swims  swiftly  to  and  fro,  up  and  down  in  the  pool.  The  difference  is 
not  merely  that  the  chemical  reactions  in  the  beetle  are  much  more  in- 
tricate than  is  the  case  with  the  potassium,  and  that  they  involve 
eventually  the  down-breaking  and  up-building  of  protein  molecules. 
The  big  difference  is  that  the  potassium  fragment  soon  flares  all  its 
activity  away  and  changes  into  something  else,  whereas  the  beetle  retains 
its  integrity  and  lasts.  It  may  be  said,  indeed,  that  it  is  only  a  difference 
in  time,  for  the  beetle  eventually  dies.  But  this  is  to  miss  the  point.  The 
peculiarity  we  are  emphasising  is  that  for  certain  variable  periods  the 
processes  of  winding-up  in  organisms  more  than  compensate  for  the 
processes  of  running  down.  A  primitive  living  creature  was  not  worthy 


of  the  name  until  it  could  balance  its  accounts  for  some  little  time, 
until  it  could  in  some  measure  counter  its  katabolism  by  its  anabolism. 
Perhaps  it  was  only  a  creature  of  a  day,  which  died  in  the  chill  of 
its  first  night,  probably  after  reproducing  its  kind;  but  the  point 
is  that  during  its  short  life  it  was  not  like  a  glorified  potassium 
fragment  or  a  clock  running  down.  It  was  to  some  extent  winding  itself 
up  as  well  as  letting  itself  run  down.  It  was  making  ends  meet 

In  the  immense  furnaces  of  the  stars,  with  unthinkably  high  tem- 
peratures, it  may  be  that  hydrogen  is  being  lifted  up  into  more  complex 
forms  of  matter,  but  on  the  earth  all  the  chemico-physical  clocks  are 
running  down.  . .  . 

In  the  little  corner  of  the  universe  where  we  move,  we  are  living 
in  a  time  of  the  running  down  of  chemico-physical  clocks.  But  the 
characteristic  of  living  organisms  is  that  they  wind  themselves  up.  .  .  . 

COLLOIDAL  PROTOPLASM. — The  accumulation  of  energy  in  organisms 
is  mainly  effected  by  storing  complex  chemical  substances,  not  merely  as 
reserves  in  the  ordinary  sense,  like  the  plant's  starch  and  the  animal's  fat, 
but  in  the  living  substance  itself  in  the  form  of  increased  protein  material. 
The  chemical  formula  of  egg-albumin,  to  take  a  familiar  protein,  is  often 
given  as  Ci428H2244N364O4G2Si4;  and  this  hints  at  the  complexity  of 
these  substances.  In  the  strict  sense,  protein  material  does  not  form 
definite  stores  in  animals,  though  it  is  a  common  reserve  in  the  seeds  of 
plants,  but  it  accumulates  as  the  amount  of  living  matter  increases.  The 
potential  chemical  energy  of  the  complex  carbon-compounds  found  in 
living  cells  is  particularly  valuable  because  the  living  matter  occurs  in  a 
colloidal  state.  Of  this  it  is  enough  to  say  that  a  watery  "solution"  holds 
in  suspension  innumerable  complex  particles,  too  small  to  be  seen,  even 
with  the  microscope,  but  large  enough  to  have  an  appreciable  surface. 
The  particles  do  not  clump  together  or  sink  because  each  carries  an 
electric  charge,  and  like  charges  repel  one  another. .  .  . 

SPECIFICITY. — Each  kind  of  organism  has  its  chemical  individuality, 
implying  a  specific  molecular  structure  in  some  of  the  important  constit- 
uents, and  a  corresponding  routine  of  reactions.  This  is  particularly  true 
of  the  proteins,  and  there  are  probably  special  proteins  for  each  genus 
at  least.  There  is  chemical  specificity  in  the  milk  of  nearly  related 
mammals,  such  as  sheep  and  goats;  and,  as  Gautier  showed  in  detail,  in 
the  grape-juices  of  nearly  related  vines.  A  stain  due  to  the  blood  of  a 
rabbit  can  be  readily  distinguished  from  a  stain  due  to  the  blood  of  a 
fowl  or  of  a  man.  More  than  that,  as  Reichert  and  Brown  have  demon- 
strated conclusively  (1909),  the  blood  of  a  horse  can  be  distinguished  from 


that  of  an  ass.  The  crystals  of  the  haemoglobin  or  red  blood  pigment  of  a 
dog  differ  from  those  of  a  wolf,  from  which  the  dog  evolved,  and 
even  from  those  of  the  Australian  dingo,  which  seems  to  be  the  result 
of  domesticated  dogs  going  wild  and  feral.  Even  the  sexes  may  be 
distinguished  by  their  blood,  and  there  are  two  or  three  cases  among 
insects  where  the  colour  of  the  male's  blood  is  different  from  the 
female's.  The  familiar  fact  that  some  men  cannot  eat  particular  kinds  of 
food,  such  as  eggs,  without  more  or  less  serious  symptoms,  is  a  vivid 
illustration  of  specificity.  It  looks  as  if  a  man  was  individual  not  merely 
in  his  finger-prints,  but  as  to  his  chemical  molecules.  Every  man  is 
his  own  laboratory.  Modern  investigation  brings  us  back  to  the  old 
saying:  "All  flesh  is  not  the  same  flesh;  but  there  is  one  kind  of  flesh  of 
men,  another  flesh  of  beasts,  another  of  fishes  and  another  of  birds."  .  .  . 
To  some  who  have  not  looked  into  the  matter  it  may  seem  almost 
preposterous  to  speak  of  a  particular  protein  for  every  genus  at  least. 
But  the  work  of  Emil  Fischer  and  others  has  shown  that  there  is  incon- 
ceivable variety  in  the  groupings  and  proportional  representations  of  the 
twenty-odd  amino-acids  and  diamino-acids  which  constitute  in  varied 
linkages  the  complex  protein  molecules.  There  must  be  a  million  million 
possibilities  and  more.  As  there  are  about  25,000  named  and  known 
species  of  Vertebrates  and  about  250,000  (some  would  say  500,000) 
named  and  known  species  of  Invertebrates,  there  may  readily  be 
particular  proteins  for  every  species  of  animal,  leaving  plenty  to  spare 
for  all  the  plants. 


The  organism's  power  of  absorbing  energy  acceleratively,  and  of  ac- 
cumulating it  beyond  its  immediate  needs,  suggests  another  triad  of 
qualities — growing,  reproducing,  and  developing,  which  may  be  profit- 
ably considered  together.  .  .  . 

GROWTH. — The  power  of  growth  must  be  taken  as  a  fundamental 
characteristic  of  organisms,  for  it  cannot  as  yet  be  re-described  in 
chemical  and  physical  terms.  The  word  is  a  convenient  label  for  a 
variety  of  processes  which  lead  to  an  increase  in  the  amount  of  living 
matter,  and  while  there  are  chemical  and  physical  factors  involved  in 
these  processes,  we  are  bound  in  the  present  state  of  science  to  admit 
that  growth  depends  on  the  veiled  tactics  of  life.  Its  results  are  extraor- 
dinary achievements,  which  would  be  astounding  if  they  were  not 
so  familiar.  From  a  microscopic  egg-cell  there  develops  an  embryo-plant 
which  may  grow,  say,  into  a  Californian  "Big  Tree" — perhaps  three 
hundred  feet  in  height  and  over  three  thousand  years  old.  A  frog  is 


about  three  or  four  inches  in  length,  its  egg-cell  is  under  a  tenth  of  an 
inch  in  diameter;  "the  mass  of  the  human  adult  is  fifteen  billion  times 
that  of  the  human  ovum."  In  the  strict  sense  growth  means  an  increase 
in  the  amount  of  the  organism's  living  matter  or  protoplasm,  but  it 
is  often  associated,  as  in  a  cucumber,  with  great  accumulation  of  water; 
or,  as  in  the  case  of  bone,  with  the  formation  of  much  in  the  way  of 
non-living  walls  around  the  living  cells.  .  .  . 

The  indispensable  condition  of  growth  is  that  income  be  greater  than 
expenditure.  A  variable  amount  of  the  food-income  is  used  to  meet 
the  everyday  expenses  of  living;  the  surplus  is  available  for  growth;  and 
this  must  be  understood  as  including,  besides  increase  in  size,  that  im- 
perceptible growth  which  brings  about  the  replacement  of  worn-out 
cells  by  fresh  ones.  Green  plants  are  great  growers  when  compared  with 
animals — the  Giant  Bamboo  may  grow  a  foot  in  a  day — and  that  is 
mainly  because  they  get  food-materials  at  a  low  chemical  level,  that  is 
to  say  from  the  air  and  the  soil-water.  Helped  by  its  chlorophyll,  the 
green  plant  is  able  to  use  part  of  the  energy  of  the  sunlight  that  bathes 
its  leaves  to  build  up  sugars,  starch,  and  proteins,  first  of  course  for 
its  own  maintenance  and  for  its  growth,  thereafter  for  "reserves,"  vari- 
ously stored  for  its  own  future,  or  that  of  its  offspring.  On  this  highly 
profitable  synthesis  and  storage  in  the  plant,  the  growth  of  all  animals 
depends — directly  in  the  case  of  the  sheep  and  other  herbivores,  in- 
directly in  the  case  of  the  tiger  and  other  carnivores. 

Food  is  thus  obviously  an  indispensable  condition  of  growth;  but 
there  are  some  puzzling  cases,  e.  g.  the  striking  growth  behaviour  of 
a  single  fragment  of  Planarian  worm,  without  food-canal,  and  thus  in- 
capable of  ingesting  food;  yet  soon  growing  a  new  head  and  posterior 
end,  fashioning  itself  anew  into  a  perfect  miniature  worm.  Here,  as  in  a 
germinating  seed,  there  must  have  been  absorption  of  water  and  utilisation 
of  the  previous  material  in  a  less  condensed  form. 

Another  curious  form  of  growth  is  expressed  in  the  replacement  of 
lost  parts,  such  as  the  claw  of  a  crab,  or  the  arm  of  a  starfish;  and  here 
again  the  body  yields  supplies.  One  of  the  most  extraordinary  instances 
of  such  replacement-growth  is  that  seen  annually  when  the  stag,  having 
dropped  his  antlers,  rapidly  grows  a  new  set,  which,  in  the  monarch, 
may  weigh  seventy  pounds! 

The  great  majority  of  animals  have  a  definite  limit  of  growth, 
an  optimum  size,  which  is  normally  attained  by  the  adult  and  rarely 
exceeded;  so  there  must  be  some  method  of  growth-regulation.  On  the 
other  hand,  some  fishes  and  reptiles  continue  growing  as  long  as  they 


live,  just  like  many  trees;  and  this  shows  that  a  limit  of  size  is  not 
fundamentally  insisted  on  by  nature. 

When  we  think  of  giants  and  dwarfs,  and  of  the  rarity  of  their 
occurrence,  the  idea  of  regulation  is  again  suggested.  So  also  when  we 
observe  the  occurrence — yet  rare  occurrence — of  monstrous  growths 
among  animals,  we  see  that  growth  is  essentially  a  regulated  increase  in 
the  amount  of  adjustment  of  living  matter.  By  what  means  is  such 
regulation  affected?  The  modern  answer  to  this  question  is  twofold. 
Regulation  is  partly  due  to  certain  hormones  (chemical  "messengers") 
which  are  produced  in  "ductless  glands"  and  distributed  by  the  blood. 
Thus  the  hormones  of  the  thyroid  gland,  and  those  of  the  pituitary  body, 
have,  among  other  functions,  that  of  growth-control.  Again,  it  has 
been  shown  that  parts  where  metabolism  is  most  intense,  e.  g.  the 
growing  point  of  a  stem,  exert  a  sway  or  dominance  over  the  growth 
of  other  parts,  as  we  shall  see  more  fully  later. 

Another  feature  of  growth  is  its  periodicity.  All  are  familiar  with  the 
rings  of  growth  on  the  cut  stem  of  a  tree,  which  mark  its  years,  through 
the  well-marked  seasonal  alternation  of  spring  and  summer  wood,  which 
are  different  in  texture.  This  instance  is  no  exceptional  case,  but  a 
vivid  illustration  of  the  rhythmic  periodicity  of  life.  The  same  is  seen 
in  the  zoning  of  fish-scales  and  the  barring  of  birds'  feathers,  and  in  the 
familiar  growth-lines  on  the  shells  of  the  seashore. 

Familiarity  is  apt  to  dull  our  eyes  to  the  marvel  of  growth — the 
annual  covering  of  the  brown  earth  with  verdure;  the  desert  blossoming 
as  the  rose;  the  spreading  of  the  green  veil  over  the  miles  of  wood- 
land; the  bamboo  rising  so  quickly  that  one  can  see  it  grow;  the  Sequoia 
or  Big  Tree  continuing  to  increase  in  bulk  for  three  thousand  years;  the 
coral-polyps  adding  chalice  to  chalice  till  they  form  a  breakwater  a 
thousand  miles  long;  the  Arctic  jellyfish  becoming  bigger  and  bigger 
till  the  disc  is  over  seven  feet  in  diameter  and  the  tentacles  trail  in 
the  waves  for  over  a  hundred  feet.  Again,  many  an  animal  egg-cell 
develops  into  a  body  that  weighs  billions  of  times  as  much  as  its 
beginning;  and  this  is  far  exceeded  in  the  growing  up  of  giants — like 
a  Blue  Whale,  eighty-five  feet  in  length,  or  an  Atlantosaurus  with  a 
thigh-bone  as  high  as  a  tall  man. 

MULTIPLICATION. — The  corollary  of  growth  is  multiplication,  a  term 
that  we  are  using  here  in  preference  to  the  more  general  word  repro- 
duction, which  includes  the  whole  series  of  functions  concerned  with 
giving  rise  to  other  organisms.  Multiplication  essentially  means  separating 
off  portions  or  buds,  spores  or  germ-cells,  which  start  a  new  generation. 
In  the  asexual  method  of  separating  off  large  pieces,  the  connection 


with  growth  is  obvious;  multiplication  occurs  as  a  consequence  of 
instabilities  which  follow  overgrowth.  As  Haeckel  said  long  ago,  repro- 
duction is  discontinuous  growth.  Its  externally  simplest  form  is  seen  in 
the  division  of  an  overgrown  unicellular  organism,  yet  in  the  everyday 
division  of  most  of  the  cells  of  plants  and  animals,  this  has  been  elabo- 
rated into  an  intricate  process,  which  secures  that  each  of  the  two 
daughter-cells  gets  a  meticulously  precise  half  of  everything  that  is  in 
the  parent-cell. 

The  connection  between  growth  and  cell-division  is  not  far  to  seek. 
Spencer,  Leuckart,  and  James  pointed  out  independently  that  as  a  cell 
of  regular  shape  increases  in  volume,  it  does  not  proportionately  increase 
in  surface.  If  it  be  a  sphere,  the  volume  of  cell-substance  or  cytoplasm  to 
be  kept  alive  increases  as  the  cube  of  the  radius,  while  the  surface, 
through  which  the  keeping  alive  is  effected,  by  various  processes  of 
diffusion,  increases  only  as  the  square.  Thus  there  tends  to  set  in  a 
hazardous  disproportion  between  volume  and  surface,  and  this  may  set 
up  instability.  The  disturbed  balance  is  normally  restored  by  the  cell 
dividing  into  two  cells.  .  .  . 

In  cases  of  sexual  reproduction,  where  germ-cells  are  separated  off  to 
start  a  new  generation,  the  relation  between  growth  and  multiplication 
is  not,  of  course,  so  direct  as  in  cases  of  asexual  reproduction  by  fission  or 
fragmentation.  It  may  be  pointed  out  that  reproduction  often  occurs  at 
the  limit  of  growth,  and  that  there  is  a  familiar  seesaw  between  feeding 
and  breeding  periods,  between  leafing  and  flowering,  between  nutrition 
and  reproduction. 

The  division  of  a  cell  is  one  of  the  wonders  of  the  world.  Bateson 
wrote:  "I  know  nothing  which  to  a  man  well  trained  in  scientific 
knowledge  and  method  brings  so  vivid  a  realisation  of  our  ignorance  of 
the  nature  of  life  as  the  mystery  of  cell-division.  ...  It  is  this  power  of 
spontaneous  division  which  most  sharply  distinguishes  the  living  from 
the  non-living.  .  .  .  The  greatest  advance  I  can  conceive  in  biology 
would  be  the  discovery  of  the  instability  which  leads  to  the  continued 
division  of  the  cell.  When  I  look  at  a  dividing  cell  I  feel  as  an  astronomer 
might  do  if  he  beheld  the  formation  of  a  double  star:  that  an  original 
act  of  creation  is  taking  place  before  me." 

In  the  present  youthful  condition  of  biology  it  is  wise  to  return 
at  frequent  intervals  to  concrete  illustrations.  We  need  the  warmth  of 
actual  facts  to  help  us  to  appreciate  the  quality  of  reproductivity  which 
we  are  only  beginning  to  understand.  In  one  day  the  multiplication  of 
a  microbe  may  result  in  a  number  with  thirty  figures.  Were  there  an 
annual  plant  with  only  two  seeds,  it  could  be  represented  by  over  a 


million  in  the  twenty-first  year.  But  a  common  British  weed  (Sisymbrium 
officinal?)  has  often  three-quarters  of  a  million  of  seeds,  so  that  in 
three  years  it  could  theoretically  cover  the  whole  earth.  Huxley  calculated 
that  if  the  descendants  of  a  single  green-fly  all  survived  and  multiplied, 
they  would,  at  the  end  of  the  first  summer,  weigh  down  the  population 
of  China.  A  codfish  is  said  to  produce  two  million  eggs,  a  conger  eel  ten 
millions,  an  oyster  twenty-millions.  The  starfish  Luidia,  according  to 
Mortensen,  produces  two  hundred  million  eggs  every  year  of  its  life. 

DEVELOPMENT. — In  active  tissues,  like  muscle  or  gland,  wear  and 
tear  is  inevitable,  especially  in  the  less  labile  parts  of  the  cells — the 
furnishings  of  life's  laboratories,  such  as  the  for  the  most  part  ultra- 
microscopic  films  that  partition  the  cyptoplasm  into  areas.  When  the 
results  of  the  wear  and  tear  over-accumulate,  they  tend  to  depress 
activity  and  in  time  to  inhibit  it;  and  this  means  ageing,  towards  death. 
But  this  decline  of  vitality  may  be  counteracted  by  rejuvenescence- 
processes  in  the  ageing  cells,  or  by  the  replacement  of  worn-out  cells  by 
new  ones.  In  some  cases  the  hard-worked  cells  go  fatally  out  of  gear, 
as  in  the  brain  of  the  busy  summer-bee,  which  does  not  usually  survive 
for  more  than  six  or  eight  weeks.  In  other  cases,  as  in  ordinary  muscle, 
the  recuperation  afforded  by  food  and  rest  is  very  perfect,  and  the  same 
cell  may  continue  active  for  many  years.  Such  cells  are  comparable  to 
the  relatively  simple  unicellular  animals,  like  the  amoebae,  which  recuper- 
ate so  thoroughly  that  they  evade  natural  death  altogether.  In  another 
set  of  cases,  e.  g.  the  lining  cells  of  the  stomach,  or  the  epithelium 
covering  the  lips,  the  senescent  cells  die  and  drop  off,  but  are  replaced  by 
others.  The  outer  epidermic  layer  of  the  skin  (the  stratum  corneum)  is 
continually  wearing  away,  and  as  continually  being  replaced  by  con- 
tributions from  the  more  intensely  living  and  growing  deeper  stratum 
(the  stratum  Malpighii).  Similarly  at  the  tip  of  a  rootlet  there  is  a 
cap  of  cells  which  are  always  dying  away  and  being  replaced  from  the 
delicate  growing  point  which  they  protect.  From  such  replacement  of  cells 
there  is  an  easy  transition  to  the  re-growth  of  lost  parts.  The  starfish 
re-grows  its  lost  arm,  the  crab  its  claw,  the  snail  its  horn,  the  earthworm 
its  head.  From  cells  below  the  plane  of  separation  there  is  in  each 
case  a  regulated  growth,  which  replaces  what  has  been  lost.  We  have 
already  mentioned  a  very  striking  instance,  in  which  regrowth  is  normal, 
and  in  organic  and  seasonal  rhythm  independent  of  any  violence  from 
without — namely,  the  re-growth  which  gives  the  stag  new  antlers  to 
replace  those  of  the  previous  year.  .  .  .  The  needful  renewal  of 
embryonic  tissue  is  rarely  seen,  unless  there  be  some  recurrent  need  for  it. 
Most  lizards  can  re-grow  their  long  tail  if  that  has  been  snapped  off  by  a 


bird  or  surrendered  in  fear  or  in  battle,  but  the  chameleon  which  keeps 
its  tail  coiled  round  the  branch,  has  not  unnaturally  lost  this  power. 
Long-limbed  animals  like  crabs,  and  starfishes  with  their  lank  arms, 
have  great  regenerative  capacity,  in  striking  contrast  to  the  compact 
and  swiftly  moving  fishes,  which  cannot  even  replace  a  lost  scale!  The 
recurrence  of  non-fatal  injuries  is  not  common  among  the  higher 
animals,  so  their  power  of  regenerating  important  parts  has  waned. 
Enough  of  this,  however;  our  present  point  is  that  the  regeneration  of 
lost  parts  illustrates  a  renewal  of  that  regulated  growth  of  complicated 
structure  which  is  characteristic  of  embryonic  development.  Out  of 
apparently  simple  cells  at  the  stump  of  a  snail's  horn,  the  whole  can  be 
regrown,  including  the  eye  at  the  tip;  and  this  may  occur  not  once  only, 
but  forty  times.  From  the  broken  portion  of  a  Begonia  leaf  there  buds  a 
complete  plant — to  root  and  shoot  and  flower.  From  such  reconstruc- 
tion there  is  but  a  step  to  the  asexual  multiplication  of  many  plants  and 
animals — whether  by  the  bulbils  of  the  lily,  the  budding  of  the  hydra 
in  the  pond,  or  the  halving  of  the  Planarian  worm.  When  the  tail-half 
of  the  dividing  Planarian  worm  proceeds  to  differentiate  a  new  head, 
with  brain-ganglia,  eyes,  and  mouth  complete,  there  is  an  obvious 
development — the  formation  of  new  and  complex  structures  out  of  the 
undifferentiated  and  apparently  simple.  .  .  . 

In  his  discussions  of  the  characteristics  of  living  creatures,  Huxley  was 
wont  to  lay  emphasis  on  what  he  called  "cyclical  development."  Within 
the  embryo-sac,  within  the  ovule,  within  the  ovary  of  the  flower,  a 
miniature  plant  is  formed  by  the  division  and  re-division  of  the 
fertilised  egg-cell.  The  ovule  becomes  a  seed;  and  this,  when  sown, 
a  seedling.  By  insensible  steps  there  is  fashioned  a  large  and  varied 
fabric,  of  root  and  shoot,  of  leaves  and  flowers.  But  sooner  or  later,  after 
this  development  is  complete,  the  grass  begins  to  wither  and  the  flower 
thereof  to  fade.  In  the  case  of  an  annual  plant,  there  is  soon  nothing 
left  but  the  seeds,  which  begin  the  cycle  anew.  .  .  . 

Among  animals  the  egg-cell,  in  many  cases  microscopic,  divides  and 
redivides,  and  an  embryo  is  built  up.  Division  of  labour  sets  in  among 
its  units.  .  .  .  Some  cells  become  nervous,  others  muscular,  others 
glandular,  others  skeletal;  and  so  the  differentiating  process  continues. 
Hereditary  contributions  from  parents  and  ancestors  find  expression, 
some  of  fundamental  importance  and  others  relatively  trivial;  the  past 
lives  on  in  the  present;  often  the  individual  shows,  in  varying  degree, 
evidence  that  it  is  "climbing  up  its  own  genealogical  tree."  Sometimes  the 
embryo  develops  steadily  and  directly  into  the  likeness  of  its  kind,  as 
in  birds  and  mammals,  with  only  traces  of  circuitousness,  such  as 


notochord  and  gill<lefts  disclose — tell-tale  evidence  of  the  lien  the  past 
continues  to  hold  on  the  present.  .  .  . 


A  third  triad  of  qualities  which  are  distinctive  of  the  living  organisms 
may  be  summed  up  in  the  words  behaviour,  registration,  and  evolution, 
in  which  as  in  previous  triads  an  underlying  unity  may  perhaps  be  dis- 

BEHAVIOUR. — Herbert  Spencer  spoke  of  life  as  "effective  response," 
and  from  the  amoeba  upwards  we  recognize  among  animals  the  power 
of  linking  actions  in  a  chain  so  that  the  result  is  behaviour — always 
purposive  and  in  the  higher  reaches  purposeful.  Responses  are  common 
in  the  inorganic  world — from  gentle  weathering  to  volcanic  explosion — 
but  non-living  things  do  not  show  the  living  creature's  power  of 
reacting  in  a  self-preservative  way.  Among  plants,  for  various  reasons, 
such  as  the  fixed  habit  of  the  great  majority  and  the  enclosing  of  the 
cells  in  cellulose,  there  is  relatively  little  exhibition  of  that  purposive 
"doing  of  things"  which  we  call  behaviour,  but  we  must  not  forget  the 
insurgent  activities  of  climbing  plants  or  the  carnivorous  adventures 
of  Venus's  Fly-trap  and  the  Sundew. 

ENREGISTRATION. — A  bar  of  iron  is  never  quite  the  same  after  it  has 
been  severely  jarred;  the  "fatigue  of  metals"  is  one  of  the  serious  risks  of 
engineering;  the  violin  suffers  from  mishandling.  But  these  are  hardly 
more  than  vague  analogies  of  the  distinctive  power  that  living  creatures 
have  of  enregistering  the  results  of  their  experience,  of  establishing 
internal  rhythms,  of  forming  habits,  and  of  remembering.  As  W.  K. 
Clifford  put  it:  "It  is  the  peculiarity  of  living  things  not  merely  that 
they  change  under  the  influence  of  surrounding  circumstances,  but  that 
any  change  which  takes  place  in  them  is  not  lost,  but  retained,  and,  as  it 
were,  built  into  the  organism,  to  serve  as  the  foundation  for  future 
action."  ...  In  various  forms  this  is  a  distinctive  feature  of  the 
living  creature. 

EVOLUTION. — In  the  attempt  to  understand  organisms  we  must  en- 
visage them  as  a  whole,  we  must  see  them  in  the  light  of  evolution. 
Thus  it  must  be  recognized  as  characteristic  of  organisms  that  they 
give  origin  to  what  is  new;  they  have  evolved  and  evolution  is  going 
on.  There  is  variability  in  the  crystalline  forms  which  the  same  substance 
may  assume;  the  modern  physicist  tells  us  of  "isotopes"  like  the  different 
kinds  of  "lead,"  which  have  the  same  chemical  properties,  yet  differ  in 
the  structure  of  the  nucleus  of  their  atoms;  the  modern  chemist  even 
assures  us  of  the  transmutation  of  elements,  thus  not  a  little  justifying  the 


medieval  alchemist's  dream  and  quest.  .  .  .  Yet  these  are  only  suggestive 
analogies;  for  the  living  organism  is  the  supreme,  though  uncon- 
scious, creative  chemist. 

No  doubt  there  are  species  that  show  nowadays  little  or  no  variation; 
there  are  conservative  living  types  that  seem  to  have  remained  the  same 
since  their  remains  were  first  buried  in  the  mud  millions  of  years  ago, 
but  the  larger  fact  is  variability.  In  multitudes  of  cases  the  offspring  show 
something  new. 

What  impressions  of  variability  we  get  at  a  "show" — whether  of  dogs 
or  pigeons,  roses  or  pansies!  Here  we  have,  as  it  were,  the  fountain  of  life 
rising  high  in  the  air — blown  into  strange  forms  by  the  breeze,  yet  modu- 
lated, to  its  own  ceaseless  waxings  and  wanings,  by  varying  pressures 
from  its  source.  Two  hundred  different  "forms"  or  varieties  are  described 
by  Jordan  in  one  of  the  commonest  of  small  Crucifers,  the  whitlow-grass 
or  Draba  verna\  and  these  are  no  longer  fluctuating  but  breeding  true. 
Again,  Lotsy  speaks  of  the  bewildering  diversity  exhibited  by  a  series  of 
about  two  hundred  specimens  of  the  Common  Buzzard  (Buteo  buteol) 
in  the  Leyden  Museum,  "hardly  two  of  which  are  alike."  .  .  . 


Our  discussions  of  living  creatures  are  apt  to  be  too  abstract  and  cold; 
we  lose  the  feeling  of  the  mysterious  which  all  life  should  suggest.  In 
our  inhibiting  conventionality  we  run  the  risk  of  false  simplification. 
Therefore,  at  the  risk  of  a  little  repetition,  we  devote  the  rest  of  this  dis- 
cussion to  what  might  be  called  "glimpses  of  life" — the  contrast  between 
the  living  creature  and  a  crystal,  the  quality  of  vital  insurgence,  the  fact 
of  organic  beauty. 

CRYSTALS  AND  ORGANISMS. — When  Linnaeus  wrote  his  famous,  yet  now 
partly  outworn,  aphorism,  "Stones  grow;  Plants  grow  and  live;  Ani- 
mals grow  and  live  and  feel,"  he  must  have  been  thinking  of  crystals. 
For  ordinary  stones  do  not  grow — except  smaller;  whereas  crystals  afford 
beautiful  illustrations  of  increase  in  size.  Suppose,  says  Sir  William  Bragg 
in  his  luminous  lectures  "Concerning  the  Nature  of  Things"  (1925), 
the  crystallographer  wishes  to  get  a  fine  big  crystal  of  common  salt,  he 
suspends  a  minute,  well-formed  crystal  in  a  solution  of  brine  at  a 
concentration  just  ready  to  form  a  salt  precipitate.  That  is  step  one.  He 
also  makes  sure  of  a  certain  temperature,  which  he  knows  from  previous 
experience  to  be  suitable  to  tempt  the  atoms  of  sodium  and  chlorine  to  give 
up  their  freedom  "when  they  meet  an  assemblage  of  atoms  already  in  per- 
fect array — that  is  to  say  when  they  come  across  a  suspended  crystal." 
Sometimes  the  solution  is  kept  in  gentle  movement  so  that  various  parts 


of  it  get  a  chance  of  meeting  the  nucleus,  which,  so  to  speak,  tempts  them 
to  settle  down — freezing  into  architecture.  Into  the  physics  of  this  we 
need  not  here  enter;  our  point  is  simply  that  in  a  suitable  environment, 
with  time  and  quiet,  a  crystal-unit  "grows."  By  accretion  it  becomes  a 
handsome  large  crystal.  Onto  its  faces  other  crystal-units  are  added,  and 
on  the  new  faces  more  again,  until  there  is  formed — an  edifice.  . . . 

The  crystal  increases  in  size  in  an  orderly  way;  how  does  this  differ 
from  the  growth  of  an  animal  or  a  plant?  Is  there  a  real  resemblance,  or 
is  it  a  misleading  analogy?  The  first  answer  is  that  a  crystal  increases  in 
size  at  the  expense  of  material,  usually  a  solution,  that  is  chemically  the 
same  as  itself;  whereas  animals  and  plants  feed  on  substances  different 
from  their  own  living  matter — often  very  different.  This  is  sound  com- 
monsense,  and  yet  the  edge  is  taken  off  it  a  little  by  two  facts,  first  that 
it  is  possible  to  feed  an  amoeba  on  amoebae,  or  a  tadpole  on  tadpoles,  or  q 
rat  on  rats;  and,  secondly,  it  is  possible  to  increase  the  size  of  a  crystal 
when  it  is  placed  in  a  solution  of  a  chemically  different  substance,  which 
has,  however,  the  same  form  of  crystallisation. 

Then  one  might  lay  emphasis  on  the  fact  that  the  increase  in  the  size 
and  weight  of  a  crystal  is  by  accretion  from  without,  whereas  organisms 
grow  by  taking  in  raw  materials,  altering  these,  and  building  from 
within.  . . . 

But  there  is  another,  more  general,  way  of  looking  at  the  difference 
between  crystal  increase  and  organic  growth:  the  one  is  passive  and  the 
other  is  active.  It  is  not  so  much  that  the  crystal  grows,  as  that  it  is  added 
to  by  other  crystal  units — usually,  moreover,  in  saturated  solution.  But  an 
organism  actively  takes  in  its  food,  actively  changes  and  distributes  it, 
and  actively  builds  with  it. 

But  some  authorities  who  press  the  analogy  between  crystals  and  crea- 
tures bring  forward  another  supposed  resemblance.  If  a  crystal  is  broken 
there  is  a  neat  mending,  provided  there  is  the  proper  environment.  There 
is  more  rapid  accretion  at  the  broken  surface  than  elsewhere;  the  repair  is 
often  in  proportion.  This  is  very  suggestive  of  the  way  in  which  an  animal 
or  a  plant  replaces  a  lost  part  or  repairs  an  injury.  If  a  crystal  be  broken 
into  two,  each  half  may  form  a  perfect  whole.  If  a  Planarian  worm  or  a 
Hydra  be  cut  across,  each  half  usually  "regenerates"  an  entire  animal. 
But  the  crystal's  "regeneration"  is  passive,  from  without,  and  homo- 
geneous; that  of  the  organism  is  active,  from  within,  and  heterogeneous. 

Another  supposed  resemblance  that  has  been  emphasised  is  the  power 
of  lying  latent  that  may  be  seen  in  crystal  and  creature  alike.  The  seed  of  a 
plant  may  remain  dry  for  a  decennium,  but  sow  it  and  it  will  germinate. 
The  egg  or  the  half-developed  embryo  of  an  animal  may  lie  unchanged 


for  many  years,  but  give  it  the  appropriate  environment  and  it  will  resume 
its  activity.  Entire  animals  like  "vinegar-eels"  may  remain  without  hint  of 
life  for  many  years;  but  it  is  only  necessary  to  put  them  in  their  proper 
surroundings  to  see  them  revive  and  multiply.  Everyone  knows  how  the 
spores  of  microbes  may  lie  low  for  a  long  time  and  be  blown  about  by  the 
wind,  but  let  one  light  on  a  suitable  medium  and  it  reasserts  its  power — 
perhaps  its  virulence  to  our  undoing. 

Now  it  is  a  similar  power  of  lying  latent  that  enthusiasts  claim  for 
crystals.  Thus  Dr.  A.  E.  H.  Tutton,  one  of  the  leading  authorities,  says: 
The  virility  of  a  crystal  is  unchanged  and  permanent.  He  pictures  very 
vividly  what  may  happen  to  a  crystal  of  quartz  detached  by  the  weather- 
ing of  a  piece  of  granite  thousands  of  years  ago.  It  may  be  "subsequently 
knocked  about  the  world  as  a  rounded  sand  grain,  blown  over  deserts  by 
the  wind,  its  corners  rounded  off  by  rude  contact  with  its  fellows  and 
subjected  to  every  variety  of  rough  treatment."  But  if  it  happen  in  our  own 
day  to  "find  itself  in  water  containing  in  solution  a  small  amount  of  the 
material  of  which  quartz  is  composed,  silicon-dioxide,  it  will  begin  to 
sprout  and  grow  again."  From  a  grain  of  sand  in  such  conditions  several 
typical  crystals  of  quartz  may  grow  out  in  different  directions.  "This 
marvellously  everlasting  power  possessed  by  a  crystal,  of  silent  imper- 
ceptible growth,  is  one  of  the  strangest  functions  of  solid  matter,  and  one 
of  the  fundamental  facts  of  science  which  is  rarely  realised,  compared  with 
many  of  the  more  obvious  phenomena  of  nature." 

But  Dr.  Tutton  chose  a  very  resistant  crystal;  what  he  says  of  the  crystal 
of  quartz  would  not  be  so  true  of  a  crystal  of  common  salt,  just  as  what 
we  said  of  the  vinegar  thread  worm  woufd  not  hold  for  the  earthworm. 
When  atoms  are  very  firmly  locked  together  in  an  intricate  space-lattice 
system  we  do  not  expect  them  to  be  changeful.  It  is  not  easy  to  induce  a 
diamond  to  change  its  state.  But  the  persistence  of  some  organisms  through 
years  of  latent  life  is  much  more  remarkable,  for  they  often  become  dry 
and  brittle,  and  thus  pass  out  of  the  colloidal  state  which  is  characteristic 
of  living  matter.  Yet  they  do  not  die.  As  for  the  prolonged  persistence 
of  some  organisms  when  they  are  not  in  a  latent  state,  the  marvel  there 
is  that  they  retain  their  intact  integrity  in  spite  of  the  ceaseless  internal 
bustle  of  metabolism.  Plus  fa  change,  plus  c'est  la  meme  chose. 

It  is  certainly  a  noteworthy  fact  that  many  kinds  of  crystals,  not  larger 
than  bacteria,  float  about  in  the  air  as  microbes  do.  And  just  as  a  microbe 
may  set  up  a  far-reaching  change  when  it  lights  on  a  suitable  medium,  so 
a  microscopic  crystal  landing  in  a  solution  which  is  in  a  properly  receptive 
condition  may  set  up  crystallisation.  But  the  differences  seem  to  us  to  be 
greater  than  the  resemblances;  for  the  minute  crystal  is  but  a  passive  peg 


to  which  molecules  attach  themselves,  while  the  microbe  is  an  active  agent 
that  attacks  the  medium  and  fills  it  with  its  progeny. 

No  one  wishes  to  think  of  living  creatures  as  if  they  had  not  antecedents 
in  the  non-living  world.  Science  is  not  partial  to  Melchizedeks.  On  the 
other  hand,  we  hold  to  the  apartness  and  uniqueness  of  life.  Dr.  A.  E.  H. 
Tutton  begins  his  fine  book  on  The  Natural  History  of  Crystals  (London, 
1924),  by  saying  that  no  definition  of  life  has  yet  been  advanced  that  will 
not  apply  equally  well  to  crystals,  but  we  have  given  reasons  for  not  accept- 
ing this  statement.  The  living  creature's  growth,  repair,  and  reproduction 
are  very  different  from  those  of  crystals;  life  is  an  enduring  activity, 
persisting  in  spite  of  its  metabolism;  the  organism  enregisters  its  experience 
and  acts  on  its  environment;  it  is  a  masterful,  even  creative,  agency.  The 
crystal,  especially  the  gem,  is  a  new  synthesis,  compared  with  the  disarray 
of  the  dust;  the  organism  is  another  and  on  a  different  line. 

THE  INSURGENCE  OF  LIFE. — It  is  difficult  to  find  the  fit  word  to  de- 
note the  quality  of  irrepressibility  and  unconquerability  which  is  char- 
acteristic of  many  living  creatures.  There  are  some,  no  doubt,  that 
drift  along,  but  it  is  much  more  characteristic  to  go  against  the  stream. 
Life  sometimes  strikes  one  as  a  tender  plant,  a  flickering  flame;  and 
who  can  forget  that  one  of  the  Ephemerides  or  mayflies  has  an  aerial 
life  of  but  a  single  hour!  At  other  times,  the  impression  we  get  is  just 
the  opposite,  for  the  living  creature  often  shows  itself  tenacious,  tough, 
and  dogged.  In  his  admirable  Introduction  to  the  Study  of  Trees  (Home 
Univ.  Library,  1927),  Dr.  Macgregor  Skene  of  Bristol  University  men- 
tions that  three  carefully  measured  stumps  of  the  "big  tree,"  Sequoia 
gigantea,  of  California  showed  rings  going  back  to  1,087,  1,122,  and  1,305 
years  B.C.  The  actual  record  for  the  second  tree  was  2,996  years  and  for 
the  third  3,197,  without  allowing  for  some  rings  that  have  been  lost  in 
the  centre.  A  specimen  of  the  dragon-tree  on  Teneriffe  is  supposed  to  be 
6,000  years  old,  and  a  bald  cypress  near  Oaxaca  in  Mexico,  no  feet  high 
with  a  circumference  of  107  feet  at  breast  height,  is  credited  with  over 
6,000  years.  As  these  giants  are  still  standing,  their  longevity  is  inferred, 
whereas  that  of  the  felled  Sequoias  is  proved  by  the  ring  counts.  But, 
in  any  case,  there  is  astounding  tenacity  of  life,  and,  without  going  out 
of  Britain,  we  may  find  other  impressive  illustrations.  For,  as  Dr.  Skene 
says,  "it  is  quite  certain  that  we  have  many  oaks  which  have  passed 
their  thousand  years,  and  some  which  may  be  much  older."  Another 
way  of  looking  at  the  insurgence  of  life  is  to  think  of  some  of  the  extraor- 
dinary haunts  which  many  living  creatures  have  sought  out.  Colonel 
Meinertzhagen,  speaking  recently  of  the  lofty  Tibetan  plateau,  directed 
attention  to  the  herds  of  antelopes  and  kiangs  (wild  ponies)  that  seem  to 


be  able  to  thrive  on  next  to  nothing!  The  explorer  marked  out  with  his 
field-glass  an  area  where  he  saw  a  small  herd  of  kiangs  feeding,  and  then 
visited  the  spot.  Measuring  a  space  one  hundred  yards  by  ten,  he  gathered 
up  every  scrap  of  vegetation,  and  the  result  was  a  quaint  collection — 
seventeen  withered  blades  of  coarse  grass  and  seven  small  alpines — not 
enough  to  feed  a  guinea-pig!  Of  course,  the  kiangs  had  been  there  before 
him,  but  there  was  little  but  very  frugal  fare  all  around.  Meinertzhagen, 
to  whom  we  owe  much  information  on  the  altitude  of  bird  flight,  saw  a 
flock  of  swifts  at  18,800  feet.  At  19,950  feet  he  shot  a  raven  which  showed 
undue  inquisitiveness  as  to  his  movements;  at  21,059  feet>  t'ie  highest 
point  reached,  he  found  a  family  of  wall-creepers — dainty  little  refugees 
of  the  mountains.  Facts  like  these  must  be  taken  into  consideration  in 
our  total  conception  of  life,  for  they  are  surely  as  essential  to  the  picture 
as  the  semi-permeability  of  the  cell-membrane,  or  any  other  fundamental 
fact  of  life-structure.  No  doubt  hunger  is  a  sharp  spur;  the  impelling 
power  of  the  struggle  for  existence  cannot  be  gainsaid;  but  we  cannot  get 
away  from  the  impression  that  we  must  also  allow  for  something 
analogous  to  the  spirit  of  adventure.  At  all  events,  the  facts  show  that 
while  the  environment  selects  organisms,  often  winnowing  very  roughly, 
there  are  other  cases  where  organisms  select  their  environment,  and  often 
adventurously.  There  is  a  quality  of  tentativeness  in  many  organisms, 
that  look  out  not  merely  for  niches  of  opportunity  into  which  to  slink, 
but  for  new  kingdoms  to  conquer. 

THE  FACT  OF  BEAUTY. — No  one  who  studies  Animate  Nature  can  get 
past  the  fact  of  Beauty.  It  is  as  real  in  its  own  way  as  the  force  of 
gravity.  It  used  to  be  spoken  of  as  though  it  were  a  quality  of  the  exotic 
— of  the  Orchid  and  the  Bird  of  Paradise — now  we  feel  it  most  at  our 
doors.  St.  Peter's  lesson  has  been  learned,  and  we  find  naught  common 
on  the  earth.  As  one  of  our  own  poets  has  said:  Beauty  crowds  us  all  our 
life.  We  maintain  that  all  living  things  are  beautiful;  save  those  which 
do  not  live  a  free  life,  those  that  are  diseased  or  parasitised,  those  that 
are  half-made,  and  those  which  bear  the  the  marks  of  man's  meddling 
fingers — monstrosities,  for  instance,  which  are  naturally  non-viable, 
but  live  a  charmed  life  under  human  protection.  With  these  excep- 
tions all  living  creatures  are  beautiful,  especially  when  we  see  them 
in  their  natural  surroundings.  To  those  who  maintain  that  Animate 
Nature  is  spotted  with  ugliness,  we  would  reply  that  they  are  allowing 
themselves  to  be  preoccupied  with  the  quite  exceptional  cases  to  which 
we  have  referred,  or  that  they  are  unable  to  attain  the  detachment 
required  in  order  to  appreciate  the  esthetic  points  of,  say,  a  snake  or  any 
other  creature  against  which  there  is  a  strong  racial  or  personal  prejudice. 


To  call  a  jellyfish  anything  but  beautiful  is  either  a  confusion  of  thought 
or  a  submission  to  some  unpleasant  association,  such  as  being  severely 
stung  when  bathing.  That  there  are  many  quaint,  whimsical,  grotesque 
creatures  must  be  granted,  to  which  conventionally  minded  zoologists 
who  should  have  known  better  have  given  names  like  Moloch  horridus, 
but  we  have  never  found  any  dubiety  in  the  enthusiasm  with  which  artists 
have  greeted  these  delightfully  grotesque  animals;  and  the  makers  of 
beauty  surely  form  the  court  of  appeal  for  all  such  cases. 

When  we  say  that  all  free-living,  fully  formed,  healthy  living  creatures 
are  beautiful,  we  mean  that  they  excite  in  the  spectator  the  characteristic 
kind  of  emotion  which  is  called  esthetic.  The  thing  of  beauty  is  a  joy  for 
ever.  The  esthetic  emotion  is  distinctive;  it  brings  no  satiety;  it  is  annexed 
to  particular  qualities  of  shape,  colour,  and  movement;  it  grows  as  we 
share  it  with  others;  it  grips  us  as  organisms,  body  and  soul,  and  remains 
with  us  incarnate.  Why  should  the  quality  of  exciting  this  distinctive  emo- 
tion be  pervasive  throughout  the  world  of  organisms,  as  compelling  in  new 
creatures  which  the  human  eye  never  saw  before  as  in  the  familiar 
favourites  with  which  our  race  has  grown  up?  It  is  possible  that  some 
light  is  thrown  on  this  question  when  we  analyse  the  esthetic  delight  which 
every  normally  constituted  man  feels  when  he  watches  the  Shetland  ponies 
racing  in  the  field,  the  kingfisher  darting  up  the  stream  like  an  arrow  made 
of  a  piece  of  rainbow,  the  mayflies  rising  in  a  living  cloud  from  a  quiet 
stretch  of  the  river,  or  the  sea-anemones  nestling  like  flowers  in  the  niches 
of  the  seashore  rocks.  The  forms,  the  colours,  the  movements,  set  up 
agreeable  rhythmic  processes  in  our  eyes,  agreeable  rhythmic  messages 
pass  to  our  brain,  and  the  good  news — the  pleasedness — is  echoed  through- 
out the  body,  in  the  pulse,  for  instance,  and  in  the  beating  of  the  heart,  as 
Wordsworth  so  well  knew.  The  esthetic  emotion  is  certainly  associated 
with  a  pleasing  bodily  resonance;  in  other  words,  it  has  its  physiological 
side.  The  second  factor  in  our  esthetic  delight  is  perceptual.  The  "form" 
of  what  we  contemplate  is  significant  for  us  and  satisfies  our  feeling.  The 
more  meaning  is  suffused  into  the  material,  the  more  our  sense  of  beauty 
is  enhanced.  The  lines  and  patterns  and  colours  of  living  creatures  go  to 
make  up  a  "form"  which  almost  never  disappoints.  .  .  .  We  suggest  for 
consideration  the  general  conclusion  that  all  free-living,  full-grown, 
wholesome  organisms  have  the  emotion-exciting  quality  of  beauty.  And 
is  not  our  humanly  sympathetic  appreciation  of  this  protean  beauty  of 
the  world  inherent  and  persistent  in  us  as  also  part  of  the  same  world  of 
life,  and  evolved  far  enough  to  realise  it  more  fully,  communicate  it  tG 
each  other  more  clearly? 




From  Microbe  Hunters 

man  named  Leeuwenhoek  looked  for  the  first  time  into  a  mysterious 
new  world  peopled  with  a  thousand  different  kinds  of  tiny  beings,  some 
ferocious  and  deadly,  others  friendly  and  useful,  many  of  them  more  im- 
portant to  mankind  than  any  continent  or  archipelago. 

Leeuwenhoek,  unsung  and  scarce  remembered,  is  now  almost  as  un- 
known as  his  strange  little  animals  and  plants  were  at  the  time  he  dis- 
covered them.  This  is  the  story  of  Leeuwenhoek,  the  first  of  the  microbe 
hunters.  .  .  .  Take  yourself  back  to  Leeuwenhoek's  day,  two  hundred  and 
fifty  years  ago,  and  imagine  yourself  just  through  high  school,  getting 
ready  to  choose  a  career,  wanting  to  know — 

You  have  lately  recovered  from  an  attack  of  mumps,  you  ask  your  father 
what  is  the  cause  of  mumps,  and  he  tells  you  a  mumpish  evil  spirit  has  got 
into  you.  His  theory  may  not  impress  you  much,  but  you  decide  to  make 
believe  you  believe  him  and  not  to  wonder  any  more  about  what  is  mumps 
— because  if  you  publicly  don't  believe  him  you  are  in  for  a  beating  and 
may  even  be  turned  out  of  the  house.  Your  father  is  Authority. 

That  was  the  world  about  three  hundred  years  ago,  when  Leeuwenhoek 
was  born.  It  had  hardly  begun  to  shake  itself  free  from  superstitions,  it  was 
barely  beginning  to  blush  for  its  ignorance.  It  was  a  world  where  science 
(which  only  means  trying  to  find  truth  by  careful  observation  and  clear 
thinking)  was  just  learning  to  toddle  on  vague  and  wobbly  legs.  It  was  a 
world  where  Servetus  was  burned  to  death  for  daring  to  cut  up  and 
examine  the  body  of  a  dead  man,  where  Galileo  was  shut  up  for  life  for 
daring  to  prove  that  the  earth  moved  around  the  sun. 



Antony  Leeuwenhoek  was  born  in  1632  amid  the  blue  windmills  and 
low  streets  and  high  canals  of  Delft,  in  Holland.  His  family  were  burghers 
of  an  intensely  respectable  kind  and  I  say  intensely  respectable  because 
they  were  basket-makers  and  brewers,  and  brewers  are  respectable  and 
highly  honored  in  Holland.  Leeuwenhoek's  father  died  early  and  his 
mother  sent  him  to  school  to  learn  to  be  a  government  official,  but  he  left 
school  at  sixteen  to  be  an  apprentice  in  a  dry-goods  store  in  Amsterdam. 
That  was  his  university. . . . 

At  the  age  of  twenty-one  he  left  the  dry-goods  store,  went  back  to  Delft, 
married,  set  up  a  dry-goods  store  of  his  own  there.  For  twenty  years  after 
that  very  little  is  known  about  him,  except  that  he  had  two  wives  (in  suc- 
cession) and  several  children  most  of  whom  died,  but  there  is  no  doubt 
that  during  this  time  he  was  appointed  janitor  of  the  city  hall  of  Delft,  and 
that  he  developed  a  most  idiotic  love  for  grinding  lenses.  He  had  heard 
that  if  you  very  carefully  ground  very  little  lenses  out  of  clear  glass,  you 
would  see  things  look  much  bigger  than  they  appeared  to  the  naked  eye. . . . 

It  would  be  great  fun  to  look  through  a  lens  and  see  things  bigger  than 
your  naked  eye  showed  them  to  you!  But  buy  lenses?  Not  Leeuwenhoek! 
There  never  was  a  more  suspicious  man.  Buy  lenses?  He  would  make 
them  himself!  During  these  twenty  years  of  his  obscurity  he  went  to  spec- 
tacle-makers and  got  the  rudiments  of  lens-grinding.  He  visited  alchemists 
and  apothecaries  and  put  his  nose  into  their  secret  ways  of  getting  metals 
from  ores,  he  began  fumblingly  to  learn  the  craft  of  the  gold-  and  silver- 
smiths. He  was  a  most  pernickety  man  and  was  not  satisfied  with  grinding 
lenses  as  good  as  those  of  the  best  lens-grinder  in  Holland,  they  had  to  be 
better  than  the  best,  and  then  he  still  fussed  over  them  for  long  hours. 
Next  he  mounted  these  lenses  in  little  oblongs  of  copper  or  silver  or  gold, 
which  he  had  extracted  himself,  over  hot  fires,  among  strange  smells  and 
fumes. . . . 

Of  course  his  neighbors  thought  he  was  a  bit  cracked  but  Leeuwenhoek 
went  on  burning  and  blistering  his  hands.  Working  forgetful  of  his 
family  and  regardless  of  his  friends,  he  bent  solitary  to  subtle  tasks  in  still 
nights.  The  good  neighbors  sniggered,  while  that  man  found  a  way  to 
make  a  tiny  lens,  less  than  one-eighth  of  an  inch  across,  so  symmetrical,  so 
perfect,  that  it  showed  little  things  to  him  with  a  fantastic  clear  enormous- 
ness. . . . 

Now  this  self-satisfied  dry-goods  dealer  began  to  turn  his  lenses  onto 
everything  he  could  get  hold  of.  He  looked  through  them  at  the  muscle 
fibers  of  a  whale  and  the  scales  of  his  own  skin.  He  went  to  the  butcher 
shop  and  begged  or  bought  ox-eyes  and  was  amazed  at  how  prettily  the 
crystalline  lens  of  the  eye  of  the  ox  is  put  together.  He  peered  for  hours  ar 


the  build  of  the  hairs  of  a  sheep,  of  a  beaver,  of  an  elk,  that  were  trans- 
formed from  their  fineness  into  great  rough  logs  under  his  bit  of  glass.  He 
delicately  dissected  the  head  of  a  fly;  he  stuck  its  brain  on  the  fine  needle 
of  his  microscope — how  he  admired  the  clear  details  of  the  marvelous  big 
brain  of  that  fly!  He  examined  the  cross-sections  of  the  wood  of  a  dozen 
different  trees  and  squinted  at  the  seeds  of  plants.  He  grunted  "Impos- 
sible!" when  he  first  spied  the  outlandish  large  perfection  of  the  sting  of  a 
flea  and  the  legs  of  a  louse.  That  man  Leeuwenhoek  was  like  a  puppy  who 
sniffs — with  a  totally  impolite  disregard  of  discrimination — at  every  object 
of  the  world  around  him! 


But  at  this  time,  in  the  middle  of  the  seventeenth  century,  great  things 
were  astir  in  the  world.  Here  and  there  in  France  and  England  and  Italy 
rare  men  were  thumbing  their  noses  at  almost  everything  that  passed  for 
knowledge.  "We  will  no  longer  take  Aristotle's  say-so,  nor  the  Pope's 
say-so,"  said  these  rebels.  "We  will  trust  only  the  perpetually  repeated 
observations  of  our  own  eyes  and  the  careful  weighings  of  our  scales;  we 
will  listen  to  the  answers  experiments  give  us  and  no  .other  answers!"  So 
in  England  a  few  of  these  revolutionists  started  a  society  called  The  Invisi- 
ble College,  it  had  to  be  invisible  because  that  man  Cromwell  might  have 
hung  them  for  plotters  and  heretics  if  he  had  heard  of  the  strange  ques- 
tions they  were  trying  to  settle. 

. . .  Remember  that  one  of  the  members  of  this  college  was  Robert  Boyle, 
founder  of  the  science  of  chemistry,  and  another  was  Isaac  Newton.  Such 
was  the  Invisible  College,  and  presently,  when  Charles  II  came  to  the 
throne,  it  rose  from  its  depths  as  a  sort  of  blind-pig  scientific  society  to  the 
dignity  of  the  name  of  the  Royal  Society  of  England.  And  they  were 
Antony  Leeuwenhoek's  first  audience!  There  was  one  man  in  Delft  who 
did  not  laugh  at  Antony  Leeuwenhoek,  and  that  was  Regnier  de  Graaf, 
whom  the  Lords  and  Gentlemen  of  the  Royal  Society  had  made  a  corre- 
sponding member  because  he  had  written  them  of  interesting  things  he 
had  found  in  the  human  ovary.  Already  Leeuwenhoek  was  rather  surly  and 
suspected  everybody,  but  he  let  de  Graaf  peep  through  those  magic  eyes 
of  his,  those  little  lenses  whose  equal  did  not  exist  in  Europe  or  England 
or  the  whole  world  for  that  matter.  What  de  Graaf  saw  through  those 
microscopes  made  him  ashamed  of  his  own  fame  and  he  hurried  to  write 
to  the  Royal  Society: 

"Get  Antony  Leeuwenhoek  to  write  you  telling  of  his  discoveries." 

And  Leeuwenhoek  answered  the  request  of  the  Royal  Society  with  all 
the  confidence  of  an  ignorant  man  who  fails  to  realize  the  profouncj 


wisdom  of  the  philosophers  he  addresses.  It  was  a  long  letter,  it  rambled 
over  every  subject  under  the  sun,  it  was  written  with  a  comical  artlessness 
in  the  conversational  Dutch  that  was  the  only  language  he  knew.  The  title 
of  that  letter  was:  "A  Specimen  of  some  Observations  made  by  a  Micro- 
scope contrived  by  Mr.  Leeuwenhoek,  concerning  Mould  upon  the  Skin, 
Flesh,  etc.;  the  Sting  of  a  Bee,  etc."  The  Royal  Society  was  amazed,  the 
sophisticated  and  learned  gentlemen  were  amused — but  principally  the 
Royal  Society  was  astounded  by  the  marvelous  things  Leeuwenhoek  told 
them  he  could  see  through  his  new  lenses.  The  Secretary  of  the  Royal 
Society  thanked  Leeuwenhoek  and  told  him  he  hoped  his  first  communica- 
tion would  be  followed  by  others.  It  was,  by  hundreds  of  others  over  a 
period  of  fifty  years.  They  were  talkative  letters  full  of  salty  remarks  about 
his  ignorant  neighbors,  of  exposures  of  charlatans  and  of  skilled  explodings 
of  superstitions,  of  chatter  about  his  personal  health — but  sandwiched  be- 
tween paragraphs  and  pages  of  this  homely  stuff,  in  almost  every  letter, 
those  Lords  and  Gentlemen  of  the  Royal  Society  had  the  honor  of  reading 
immortal  and  gloriously  accurate  descriptions  of  the  discoveries  made  by 
the  magic  eye  of  that  janitor  and  shopkeeper.  What  discoveries! 

.  .  .  When  Leeuwenhoek  was  born  there  were  no  microscopes  but  only 
crude  hand-lenses  that  would  hardly  make  a  ten-cent  piece  look  as  large  as 
a  quarter.  Through  these — without  his  incessant  grinding  of  his  own  mar- 
velous lenses — that  Dutchman  might  have  looked  till  he  grew  old  without 
discovering  any  creature  smaller  than  a  cheese-mite.  You  have  read  that 
he  made  better  and  better  lenses  with  the  fanatical  persistence  of  a  lunatic; 
that  he  examined  everything,  the  most  intimate  things  and  the  most 
shocking  things,  with  the  silly  curiosity  of  a  puppy.  Yes,  and  all  this 
squinting  at  bee-stings  and  mustache  hairs  and  what-not  were  needful  to 
prepare  him  for  that  sudden  day  when  he  looked  through  his  toy  of  a  gold- 
mounted  lens  at  a  fraction  of  a  small  drop  of  clear  rain  water  to  discover — 

What  he  saw  that  day  starts  this  history.  Leeuwenhoek  was  a  maniac  ob- 
server, and  who  but  such  a  strange  man  would  have  thought  to  turn  his 
lens  on  clear,  pure  water,  just  come  down  from  the  sky?  What  could  there 
be  in  water  but  just — water?  You  can  imagine  his  daughter  Maria — she 
was  nineteen  and  she  took  such  care  of  her  slightly  insane  father! — watch- 
ing him  take  a  little  tube  of  glass,  heat  it  red-hot  in  a  flame,  draw  it  out  to 
the  thinnest  of  a  hair. . . . 

He  squints  through  his  lens.  He  mutters  guttural  words  under  his 
breath.  . . . 

Then  suddenly  the  excited  voice  of  Leeuwenhoek:  "Come  here!  Hurry! 
There  are  little  animals  in  this  rain  water.  .  .  .  They  swim!  They  play 


around!  They  are  a  thousand  times  smaller  than  any  creatures  we  can  see 
with  our  eyes  alone. . . .  Look!  See  what  I  have  discovered!" 

Leeuwenhoek's  day  of  days  had  come.  .  .  .  This  janitor  of  Delft  had 
stolen  upon  and  peeped  into  a  fantastic  sub-visible  world  of  little  things, 
creatures  that  had  lived,  had  bred,  had  battled,  had  died,  completely 
hidden  from  and  unknown  to  all  men  from  the  beginning  of  time.  Beasts 
these  were  of  a  kind  that  ravaged  and  annihilated  whole  races  of  men  ten 
millions  times  larger  than  they  were  themselves.  Beings  these  were,  more 
terrible  than  fire-spitting  dragons  or  hydra-headed  monsters.  They  were 
silent  assassins  that  murdered  babes  in  warm  cradles  and  kings  in  sheltered 
places.  It  was  this  invisible,  insignificant,  but  implacable — and  sometimes 
friendly — world  that  Leeuwenhoek  had  looked  into  for  the  first  time  of  all 
men  of  all  countries. 

This  was  Leeuwenhoek's  day  of  days. . . . 


.  .  .  How  marvelous  it  would  be  to  step  into  that  simple  Dutchman's 
shoes,  to  be  inside  his  brain  and  body,  to  feel  his  excitement — it  is  almost 
nausea! — at  his  first  peep  at  those  cavorting  "wretched  beasties." 

That  was  what  he  called  them,  and  this  Leeuwenhoek  was  an  unsure 
man.  Those  animals  were  too  tremendousl